diff --git a/bot/core/__pycache__/scheduler.cpython-312.pyc b/bot/core/__pycache__/scheduler.cpython-312.pyc
index 4c21641..5741813 100644
Binary files a/bot/core/__pycache__/scheduler.cpython-312.pyc and b/bot/core/__pycache__/scheduler.cpython-312.pyc differ
diff --git a/bot/core/scheduler.py b/bot/core/scheduler.py
index 583221b..0f80a17 100644
--- a/bot/core/scheduler.py
+++ b/bot/core/scheduler.py
@@ -1,14 +1,12 @@
 """Scheduler for sending reminder notifications."""
 
 import asyncio
-from datetime import datetime
 from typing import Optional
 
 from aiogram import Bot
 from apscheduler.schedulers.asyncio import AsyncIOScheduler
 from apscheduler.triggers.interval import IntervalTrigger
 
-from bot.db.base import get_session
 from bot.db.operations import get_due_reminders
 from bot.keyboards.reminders import get_reminder_notification_keyboard
 from bot.services.time_service import get_time_service
@@ -50,7 +48,6 @@ async def check_and_send_reminders(bot: Bot) -> None:
         bot: Bot instance
     """
     from bot.db.base import async_session_maker
-    from bot.db.operations import update_reminder
 
     if not async_session_maker:
         logger.error("Session maker not initialized")
@@ -60,7 +57,6 @@ async def check_and_send_reminders(bot: Bot) -> None:
         time_service = get_time_service()
         current_time = time_service.get_now()
 
-        # Get due reminders from database using proper async session
         async with async_session_maker() as session:
             due_reminders = await get_due_reminders(session, current_time)
 
@@ -70,7 +66,6 @@ async def check_and_send_reminders(bot: Bot) -> None:
 
             logger.info(f"Found {len(due_reminders)} due reminders")
 
-            # Send notifications
             for reminder in due_reminders:
                 await send_reminder_notification(
                     bot=bot,
@@ -79,20 +74,17 @@ async def check_and_send_reminders(bot: Bot) -> None:
                     text=reminder.text,
                 )
 
-                # Update next_run_at to prevent sending again
-                # (it will be properly updated when user clicks "Done" or by periodic update)
-                temp_next_run = time_service.calculate_next_occurrence(
+                next_run = time_service.calculate_next_occurrence(
                     current_run=reminder.next_run_at,
                     days_interval=reminder.days_interval,
                 )
-                await update_reminder(session, reminder.id, next_run_at=temp_next_run)
+                reminder.next_run_at = next_run
+                reminder.updated_at = time_service.get_now()
+
+                await asyncio.sleep(0.5)
 
-            # Commit all updates
             await session.commit()
 
-            # Small delay to avoid rate limits
-            await asyncio.sleep(0.5)
-
     except Exception as e:
         logger.error(f"Error in check_and_send_reminders: {e}", exc_info=True)
 
diff --git a/bot/db/__pycache__/models.cpython-312.pyc b/bot/db/__pycache__/models.cpython-312.pyc
new file mode 100644
index 0000000..6834c04
Binary files /dev/null and b/bot/db/__pycache__/models.cpython-312.pyc differ
diff --git a/bot/db/__pycache__/operations.cpython-312.pyc b/bot/db/__pycache__/operations.cpython-312.pyc
new file mode 100644
index 0000000..e3ccf5e
Binary files /dev/null and b/bot/db/__pycache__/operations.cpython-312.pyc differ
diff --git a/bot/db/models.py b/bot/db/models.py
index c608268..fde73ca 100644
--- a/bot/db/models.py
+++ b/bot/db/models.py
@@ -8,6 +8,11 @@ from sqlalchemy.orm import Mapped, mapped_column, relationship
 from bot.db.base import Base
 
 
+def _now_local() -> datetime:
+    from bot.services.time_service import get_time_service
+    return get_time_service().get_now()
+
+
 class User(Base):
     """User model - represents Telegram users."""
 
@@ -18,9 +23,9 @@ class User(Base):
     username: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
     first_name: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
     last_name: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
-    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, nullable=False)
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=_now_local, nullable=False)
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False
+        DateTime, default=_now_local, onupdate=_now_local, nullable=False
     )
     is_active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
 
@@ -44,9 +49,9 @@ class Reminder(Base):
     next_run_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, index=True)
     last_done_at: Mapped[Optional[datetime]] = mapped_column(DateTime, nullable=True)
     is_active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
-    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, nullable=False)
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=_now_local, nullable=False)
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False
+        DateTime, default=_now_local, onupdate=_now_local, nullable=False
     )
 
     # Optional fields for statistics
diff --git a/bot/db/operations.py b/bot/db/operations.py
index 486a871..fc2ad2f 100644
--- a/bot/db/operations.py
+++ b/bot/db/operations.py
@@ -1,11 +1,11 @@
 """CRUD operations for database models."""
 
-from datetime import datetime
+from datetime import datetime, time
 from typing import Optional, List
 from sqlalchemy import select, update, delete
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from bot.db.models import User, Reminder
+from bot.db.models import User, Reminder, _now_local
 from bot.logging_config import get_logger
 
 logger = get_logger(__name__)
@@ -46,7 +46,7 @@ async def get_or_create_user(
             user.username = username
             user.first_name = first_name
             user.last_name = last_name
-            user.updated_at = datetime.utcnow()
+            user.updated_at = _now_local()
             await session.commit()
             logger.debug(f"Updated user info: {tg_user_id}")
         return user
@@ -90,7 +90,7 @@ async def create_reminder(
     user_id: int,
     text: str,
     days_interval: int,
-    time_of_day: datetime.time,
+    time_of_day: time,
     next_run_at: datetime,
 ) -> Reminder:
     """
@@ -212,7 +212,7 @@ async def update_reminder(
         if hasattr(reminder, key):
             setattr(reminder, key, value)
 
-    reminder.updated_at = datetime.utcnow()
+    reminder.updated_at = _now_local()
     await session.commit()
     await session.refresh(reminder)
     logger.debug(f"Updated reminder {reminder_id}")
@@ -261,10 +261,10 @@ async def mark_reminder_done(
     if not reminder:
         return None
 
-    reminder.last_done_at = datetime.utcnow()
+    reminder.last_done_at = _now_local()
     reminder.next_run_at = next_run_at
     reminder.total_done_count += 1
-    reminder.updated_at = datetime.utcnow()
+    reminder.updated_at = _now_local()
 
     await session.commit()
     await session.refresh(reminder)
@@ -294,7 +294,7 @@ async def snooze_reminder(
 
     reminder.next_run_at = next_run_at
     reminder.snooze_count += 1
-    reminder.updated_at = datetime.utcnow()
+    reminder.updated_at = _now_local()
 
     await session.commit()
     await session.refresh(reminder)
@@ -323,7 +323,7 @@ async def toggle_reminder_active(
         return None
 
     reminder.is_active = is_active
-    reminder.updated_at = datetime.utcnow()
+    reminder.updated_at = _now_local()
 
     await session.commit()
     await session.refresh(reminder)
diff --git a/bot/handlers/__pycache__/callbacks.cpython-312.pyc b/bot/handlers/__pycache__/callbacks.cpython-312.pyc
index ce2b300..2a70de5 100644
Binary files a/bot/handlers/__pycache__/callbacks.cpython-312.pyc and b/bot/handlers/__pycache__/callbacks.cpython-312.pyc differ
diff --git a/bot/handlers/__pycache__/errors.cpython-312.pyc b/bot/handlers/__pycache__/errors.cpython-312.pyc
index 558a073..8e9d386 100644
Binary files a/bot/handlers/__pycache__/errors.cpython-312.pyc and b/bot/handlers/__pycache__/errors.cpython-312.pyc differ
diff --git a/bot/handlers/__pycache__/reminders_create.cpython-312.pyc b/bot/handlers/__pycache__/reminders_create.cpython-312.pyc
index 267a881..30f51e0 100644
Binary files a/bot/handlers/__pycache__/reminders_create.cpython-312.pyc and b/bot/handlers/__pycache__/reminders_create.cpython-312.pyc differ
diff --git a/bot/handlers/__pycache__/reminders_manage.cpython-312.pyc b/bot/handlers/__pycache__/reminders_manage.cpython-312.pyc
index fc73270..d9e9c00 100644
Binary files a/bot/handlers/__pycache__/reminders_manage.cpython-312.pyc and b/bot/handlers/__pycache__/reminders_manage.cpython-312.pyc differ
diff --git a/bot/handlers/callbacks.py b/bot/handlers/callbacks.py
index 22606cb..21f6f16 100644
--- a/bot/handlers/callbacks.py
+++ b/bot/handlers/callbacks.py
@@ -20,10 +20,36 @@ logger = get_logger(__name__)
 
 router = Router(name="callbacks")
 reminders_service = RemindersService()
-time_service = get_time_service()
 
 
-# ==================== Done Action ====================
+async def _verify_owner(
+    session: AsyncSession,
+    reminder_id: int,
+    tg_user_id: int,
+) -> bool:
+    """Fetch reminder and verify it belongs to tg_user_id."""
+    from sqlalchemy.orm import selectinload
+    from sqlalchemy import select
+    from bot.db.models import Reminder
+
+    result = await session.execute(
+        select(Reminder)
+        .options(selectinload(Reminder.user))
+        .where(Reminder.id == reminder_id)
+    )
+    reminder = result.scalar_one_or_none()
+
+    if not reminder:
+        return False
+    if reminder.user.tg_user_id != tg_user_id:
+        return False
+    return True
+
+
+@router.callback_query(F.data == "noop")
+async def handle_noop(callback: CallbackQuery) -> None:
+    """Handle noop callback (page counter button)."""
+    await callback.answer()
 
 
 @router.callback_query(ReminderActionCallback.filter(F.action == "done"))
@@ -32,21 +58,18 @@ async def handle_done(
     callback_data: ReminderActionCallback,
     session: AsyncSession,
 ) -> None:
-    """
-    Handle 'Done' button - mark reminder as completed.
+    """Handle 'Done' button - mark reminder as completed."""
+    owner_check = await _verify_owner(session, callback_data.reminder_id, callback.from_user.id)
+    if not owner_check:
+        await callback.answer("Напоминание не найдено", show_alert=True)
+        return
 
-    Args:
-        callback: Callback query
-        callback_data: Parsed callback data
-        session: Database session
-    """
     reminder = await reminders_service.mark_as_done(session, callback_data.reminder_id)
-
     if not reminder:
         await callback.answer("Напоминание не найдено", show_alert=True)
         return
 
-    next_run_str = time_service.format_next_run(reminder.next_run_at)
+    next_run_str = get_time_service().format_next_run(reminder.next_run_at)
 
     await callback.message.edit_text(
         f"✅ Отлично! Отметил как выполненное.\n\n"
@@ -57,21 +80,18 @@ async def handle_done(
     logger.info(f"Reminder {reminder.id} marked as done by user {callback.from_user.id}")
 
 
-# ==================== Snooze Action ====================
-
-
 @router.callback_query(ReminderActionCallback.filter(F.action == "snooze"))
 async def handle_snooze_select(
     callback: CallbackQuery,
     callback_data: ReminderActionCallback,
+    session: AsyncSession,
 ) -> None:
-    """
-    Handle 'Snooze' button - show delay options.
+    """Handle 'Snooze' button - show delay options."""
+    owner_check = await _verify_owner(session, callback_data.reminder_id, callback.from_user.id)
+    if not owner_check:
+        await callback.answer("Напоминание не найдено", show_alert=True)
+        return
 
-    Args:
-        callback: Callback query
-        callback_data: Parsed callback data
-    """
     await callback.message.edit_text(
         "На сколько отложить напоминание?",
         reply_markup=get_snooze_delay_keyboard(callback_data.reminder_id),
@@ -85,23 +105,20 @@ async def handle_snooze_delay(
     callback_data: SnoozeDelayCallback,
     session: AsyncSession,
 ) -> None:
-    """
-    Handle snooze delay selection.
+    """Handle snooze delay selection."""
+    owner_check = await _verify_owner(session, callback_data.reminder_id, callback.from_user.id)
+    if not owner_check:
+        await callback.answer("Напоминание не найдено", show_alert=True)
+        return
 
-    Args:
-        callback: Callback query
-        callback_data: Parsed callback data
-        session: Database session
-    """
     reminder = await reminders_service.snooze(
         session, callback_data.reminder_id, callback_data.hours
     )
-
     if not reminder:
         await callback.answer("Напоминание не найдено", show_alert=True)
         return
 
-    next_run_str = time_service.format_next_run(reminder.next_run_at)
+    next_run_str = get_time_service().format_next_run(reminder.next_run_at)
 
     await callback.message.edit_text(
         f"⏰ Напоминание отложено.\n\n"
@@ -115,25 +132,19 @@ async def handle_snooze_delay(
     )
 
 
-# ==================== Pause/Resume Actions ====================
-
-
 @router.callback_query(ReminderActionCallback.filter(F.action == "pause"))
 async def handle_pause(
     callback: CallbackQuery,
     callback_data: ReminderActionCallback,
     session: AsyncSession,
 ) -> None:
-    """
-    Handle 'Pause' button - deactivate reminder.
+    """Handle 'Pause' button - deactivate reminder."""
+    owner_check = await _verify_owner(session, callback_data.reminder_id, callback.from_user.id)
+    if not owner_check:
+        await callback.answer("Напоминание не найдено", show_alert=True)
+        return
 
-    Args:
-        callback: Callback query
-        callback_data: Parsed callback data
-        session: Database session
-    """
     reminder = await reminders_service.pause_reminder(session, callback_data.reminder_id)
-
     if not reminder:
         await callback.answer("Напоминание не найдено", show_alert=True)
         return
@@ -153,21 +164,18 @@ async def handle_resume(
     callback_data: ReminderActionCallback,
     session: AsyncSession,
 ) -> None:
-    """
-    Handle 'Resume' button - reactivate reminder.
+    """Handle 'Resume' button - reactivate reminder."""
+    owner_check = await _verify_owner(session, callback_data.reminder_id, callback.from_user.id)
+    if not owner_check:
+        await callback.answer("Напоминание не найдено", show_alert=True)
+        return
 
-    Args:
-        callback: Callback query
-        callback_data: Parsed callback data
-        session: Database session
-    """
     reminder = await reminders_service.resume_reminder(session, callback_data.reminder_id)
-
     if not reminder:
         await callback.answer("Напоминание не найдено", show_alert=True)
         return
 
-    next_run_str = time_service.format_next_run(reminder.next_run_at)
+    next_run_str = get_time_service().format_next_run(reminder.next_run_at)
 
     await callback.message.edit_text(
         f"▶️ Напоминание возобновлено!\n\n"
@@ -178,21 +186,18 @@ async def handle_resume(
     logger.info(f"Reminder {reminder.id} resumed by user {callback.from_user.id}")
 
 
-# ==================== Delete Action ====================
-
-
 @router.callback_query(ReminderActionCallback.filter(F.action == "delete"))
 async def handle_delete_confirm(
     callback: CallbackQuery,
     callback_data: ReminderActionCallback,
+    session: AsyncSession,
 ) -> None:
-    """
-    Handle 'Delete' button - ask for confirmation.
+    """Handle 'Delete' button - ask for confirmation."""
+    owner_check = await _verify_owner(session, callback_data.reminder_id, callback.from_user.id)
+    if not owner_check:
+        await callback.answer("Напоминание не найдено", show_alert=True)
+        return
 
-    Args:
-        callback: Callback query
-        callback_data: Parsed callback data
-    """
     await callback.message.edit_text(
         "Точно удалить напоминание?",
         reply_markup=get_confirmation_keyboard(
@@ -209,14 +214,7 @@ async def handle_delete_execute(
     callback_data: ConfirmCallback,
     session: AsyncSession,
 ) -> None:
-    """
-    Execute reminder deletion after confirmation.
-
-    Args:
-        callback: Callback query
-        callback_data: Parsed callback data
-        session: Database session
-    """
+    """Execute reminder deletion after confirmation."""
     if callback_data.action == "no":
         await callback.message.edit_text("Удаление отменено.")
         await callback.answer()
@@ -238,17 +236,9 @@ async def handle_delete_execute(
     )
 
 
-# ==================== Settings Placeholder ====================
-
-
 @router.message(F.text == "⚙️ Настройки")
 async def handle_settings(message: Message) -> None:
-    """
-    Handle settings button (placeholder).
-
-    Args:
-        message: Telegram message
-    """
+    """Handle settings button (placeholder)."""
     await message.answer(
         "⚙️ Настройки\n\n"
         "Функционал настроек будет добавлен в следующих версиях.\n\n"
diff --git a/bot/handlers/errors.py b/bot/handlers/errors.py
index e47bcff..9669738 100644
--- a/bot/handlers/errors.py
+++ b/bot/handlers/errors.py
@@ -2,7 +2,6 @@
 
 from aiogram import Router
 from aiogram.types import ErrorEvent
-from aiogram.exceptions import TelegramBadRequest
 
 from bot.logging_config import get_logger
 
@@ -12,7 +11,7 @@ router = Router(name="errors")
 
 
 @router.error()
-async def error_handler(event: ErrorEvent) -> None:
+async def error_handler(event: ErrorEvent) -> bool:
     """
     Global error handler for all unhandled exceptions.
 
@@ -41,3 +40,5 @@ async def error_handler(event: ErrorEvent) -> None:
             )
         except Exception as e:
             logger.error(f"Failed to send error callback to user: {e}")
+
+    return True
diff --git a/bot/handlers/reminders_create.py b/bot/handlers/reminders_create.py
index 7a3f4a3..9908703 100644
--- a/bot/handlers/reminders_create.py
+++ b/bot/handlers/reminders_create.py
@@ -24,7 +24,6 @@ logger = get_logger(__name__)
 
 router = Router(name="reminders_create")
 reminders_service = RemindersService()
-time_service = get_time_service()
 
 
 @router.message(F.text == "➕ Новое напоминание")
@@ -42,7 +41,7 @@ async def start_create_reminder(message: Message, state: FSMContext) -> None:
     )
 
 
-@router.message(CreateReminderStates.waiting_for_text)
+@router.message(CreateReminderStates.waiting_for_text, F.text)
 async def process_reminder_text(message: Message, state: FSMContext) -> None:
     """
     Process reminder text input.
@@ -106,7 +105,7 @@ async def process_interval_button(
     await callback.answer()
 
 
-@router.message(CreateReminderStates.waiting_for_interval)
+@router.message(CreateReminderStates.waiting_for_interval, F.text)
 async def process_interval_text(message: Message, state: FSMContext) -> None:
     """
     Process interval input as text.
@@ -134,7 +133,7 @@ async def process_interval_text(message: Message, state: FSMContext) -> None:
     )
 
 
-@router.message(CreateReminderStates.waiting_for_time)
+@router.message(CreateReminderStates.waiting_for_time, F.text)
 async def process_reminder_time(message: Message, state: FSMContext) -> None:
     """
     Process reminder time input.
@@ -225,7 +224,7 @@ async def process_create_confirmation(
     await state.clear()
 
     # Format next run time
-    next_run_str = time_service.format_next_run(reminder.next_run_at)
+    next_run_str = get_time_service().format_next_run(reminder.next_run_at)
 
     await callback.message.edit_text(
         f"✅ Напоминание создано!\n\n"
@@ -238,3 +237,11 @@ async def process_create_confirmation(
     await callback.answer("Напоминание создано!")
 
     logger.info(f"User {user.tg_user_id} created reminder {reminder.id}")
+
+
+@router.message(CreateReminderStates.waiting_for_text)
+@router.message(CreateReminderStates.waiting_for_interval)
+@router.message(CreateReminderStates.waiting_for_time)
+async def fsm_non_text_fallback(message: Message) -> None:
+    """Fallback for non-text messages during FSM creation flow."""
+    await message.answer("Пожалуйста, отправь текстовое сообщение.")
diff --git a/bot/handlers/reminders_manage.py b/bot/handlers/reminders_manage.py
index ead7264..76e6d4f 100644
--- a/bot/handlers/reminders_manage.py
+++ b/bot/handlers/reminders_manage.py
@@ -259,7 +259,7 @@ async def edit_text_start(
     await callback.answer()
 
 
-@router.message(EditReminderStates.editing_text)
+@router.message(EditReminderStates.editing_text, F.text)
 async def edit_text_process(
     message: Message,
     state: FSMContext,
@@ -368,7 +368,7 @@ async def edit_interval_button(
     await callback.answer("Обновлено!")
 
 
-@router.message(EditReminderStates.editing_interval)
+@router.message(EditReminderStates.editing_interval, F.text)
 async def edit_interval_text(
     message: Message,
     state: FSMContext,
@@ -429,7 +429,7 @@ async def edit_time_start(
     await callback.answer()
 
 
-@router.message(EditReminderStates.editing_time)
+@router.message(EditReminderStates.editing_time, F.text)
 async def edit_time_process(
     message: Message,
     state: FSMContext,
@@ -466,3 +466,11 @@ async def edit_time_process(
         f"✅ Время обновлено!\n\nНовое время: {time_of_day.strftime('%H:%M')}",
         reply_markup=get_main_menu_keyboard(),
     )
+
+
+@router.message(EditReminderStates.editing_text)
+@router.message(EditReminderStates.editing_interval)
+@router.message(EditReminderStates.editing_time)
+async def edit_non_text_fallback(message: Message) -> None:
+    """Fallback for non-text messages during FSM edit flow."""
+    await message.answer("Пожалуйста, отправь текстовое сообщение.")
diff --git a/bot/keyboards/__pycache__/pagination.cpython-312.pyc b/bot/keyboards/__pycache__/pagination.cpython-312.pyc
new file mode 100644
index 0000000..f983945
Binary files /dev/null and b/bot/keyboards/__pycache__/pagination.cpython-312.pyc differ
diff --git a/bot/keyboards/pagination.py b/bot/keyboards/pagination.py
index 50217e3..e6f3841 100644
--- a/bot/keyboards/pagination.py
+++ b/bot/keyboards/pagination.py
@@ -5,6 +5,7 @@ from aiogram.types import InlineKeyboardMarkup, InlineKeyboardButton
 from aiogram.filters.callback_data import CallbackData
 
 from bot.db.models import Reminder
+from bot.utils.formatting import truncate_text
 
 
 class PaginationCallback(CallbackData, prefix="page"):
@@ -39,7 +40,7 @@ def get_reminders_list_keyboard(
     # Add buttons for reminders on current page
     for reminder in reminders[start_idx:end_idx]:
         status_icon = "✅" if reminder.is_active else "⏸"
-        button_text = f"{status_icon} #{reminder.id} {reminder.text[:30]}..."
+        button_text = f"{status_icon} #{reminder.id} {truncate_text(reminder.text, 30)}"
 
         buttons.append([
             InlineKeyboardButton(
diff --git a/bot/services/__pycache__/reminders_service.cpython-312.pyc b/bot/services/__pycache__/reminders_service.cpython-312.pyc
new file mode 100644
index 0000000..747f4a2
Binary files /dev/null and b/bot/services/__pycache__/reminders_service.cpython-312.pyc differ
diff --git a/bot/services/__pycache__/time_service.cpython-312.pyc b/bot/services/__pycache__/time_service.cpython-312.pyc
new file mode 100644
index 0000000..54d531f
Binary files /dev/null and b/bot/services/__pycache__/time_service.cpython-312.pyc differ
diff --git a/bot/services/reminders_service.py b/bot/services/reminders_service.py
index 9a881ff..37c1cc9 100644
--- a/bot/services/reminders_service.py
+++ b/bot/services/reminders_service.py
@@ -25,9 +25,9 @@ logger = get_logger(__name__)
 class RemindersService:
     """Service for reminder-related operations."""
 
-    def __init__(self):
-        """Initialize RemindersService."""
-        self.time_service = get_time_service()
+    @property
+    def time_service(self):
+        return get_time_service()
 
     async def create_new_reminder(
         self,
@@ -50,13 +50,10 @@ class RemindersService:
         Returns:
             Created Reminder instance
         """
-        # Calculate next run time
-        next_run_at = self.time_service.calculate_next_run_time(
+        next_run_at = self.time_service.calculate_first_run_time(
             time_of_day=time_of_day,
-            days_interval=days_interval,
         )
 
-        # Create reminder
         reminder = await create_reminder(
             session=session,
             user_id=user_id,
@@ -134,7 +131,7 @@ class RemindersService:
         new_days_interval: int,
     ) -> Optional[Reminder]:
         """
-        Update reminder interval.
+        Update reminder interval and recalculate next_run_at with new interval.
 
         Args:
             session: Database session
@@ -148,8 +145,7 @@ class RemindersService:
         if not reminder:
             return None
 
-        # Recalculate next_run_at with new interval
-        next_run_at = self.time_service.calculate_next_run_time(
+        next_run_at = self.time_service.calculate_next_run_with_interval(
             time_of_day=reminder.time_of_day,
             days_interval=new_days_interval,
         )
@@ -168,7 +164,7 @@ class RemindersService:
         new_time_of_day: time,
     ) -> Optional[Reminder]:
         """
-        Update reminder time.
+        Update reminder time and recalculate next_run_at.
 
         Args:
             session: Database session
@@ -182,10 +178,8 @@ class RemindersService:
         if not reminder:
             return None
 
-        # Recalculate next_run_at with new time
-        next_run_at = self.time_service.calculate_next_run_time(
+        next_run_at = self.time_service.calculate_first_run_time(
             time_of_day=new_time_of_day,
-            days_interval=reminder.days_interval,
         )
 
         return await update_reminder(
@@ -231,7 +225,6 @@ class RemindersService:
         if not reminder:
             return None
 
-        # Calculate next occurrence
         next_run_at = self.time_service.calculate_next_occurrence(
             current_run=reminder.next_run_at,
             days_interval=reminder.days_interval,
@@ -284,7 +277,7 @@ class RemindersService:
         reminder_id: int,
     ) -> Optional[Reminder]:
         """
-        Resume (activate) a reminder.
+        Resume (activate) a reminder. Recalculates next_run_at atomically.
 
         Args:
             session: Database session
@@ -297,12 +290,13 @@ class RemindersService:
         if not reminder:
             return None
 
-        # Recalculate next_run_at from now
-        next_run_at = self.time_service.calculate_next_run_time(
+        next_run_at = self.time_service.calculate_first_run_time(
             time_of_day=reminder.time_of_day,
-            days_interval=reminder.days_interval,
         )
 
-        # Update and activate
-        await update_reminder(session, reminder_id, next_run_at=next_run_at)
-        return await toggle_reminder_active(session, reminder_id, is_active=True)
+        return await update_reminder(
+            session,
+            reminder_id,
+            next_run_at=next_run_at,
+            is_active=True,
+        )
diff --git a/bot/services/time_service.py b/bot/services/time_service.py
index 68684cb..04691ea 100644
--- a/bot/services/time_service.py
+++ b/bot/services/time_service.py
@@ -46,14 +46,41 @@ class TimeService:
         """
         return datetime.combine(date.date(), time_of_day)
 
-    def calculate_next_run_time(
+    def calculate_first_run_time(
+        self,
+        time_of_day: time,
+        from_datetime: Optional[datetime] = None,
+    ) -> datetime:
+        """
+        Calculate the nearest future occurrence of time_of_day (today or tomorrow).
+        Used for new reminders and resume.
+
+        Args:
+            time_of_day: Desired time of day
+            from_datetime: Base datetime (defaults to now)
+
+        Returns:
+            Next run datetime (today if time hasn't passed, otherwise tomorrow)
+        """
+        if from_datetime is None:
+            from_datetime = self.get_now()
+
+        next_run = self.combine_date_time(from_datetime, time_of_day)
+
+        if next_run <= from_datetime:
+            next_run += timedelta(days=1)
+
+        return next_run
+
+    def calculate_next_run_with_interval(
         self,
         time_of_day: time,
         days_interval: int,
         from_datetime: Optional[datetime] = None,
     ) -> datetime:
         """
-        Calculate next run datetime for a reminder.
+        Calculate next run datetime using interval offset from now.
+        Used when interval is changed.
 
         Args:
             time_of_day: Desired time of day
@@ -61,19 +88,13 @@ class TimeService:
             from_datetime: Base datetime (defaults to now)
 
         Returns:
-            Next run datetime
+            Datetime at time_of_day, days_interval days from from_datetime
         """
         if from_datetime is None:
             from_datetime = self.get_now()
 
-        # Start with today at the specified time
-        next_run = self.combine_date_time(from_datetime, time_of_day)
-
-        # If the time has already passed today, start from tomorrow
-        if next_run <= from_datetime:
-            next_run += timedelta(days=1)
-
-        return next_run
+        target_date = from_datetime + timedelta(days=days_interval)
+        return self.combine_date_time(target_date, time_of_day)
 
     def calculate_next_occurrence(
         self,
@@ -81,16 +102,23 @@ class TimeService:
         days_interval: int,
     ) -> datetime:
         """
-        Calculate next occurrence after a completed reminder.
+        Calculate next occurrence after a completed/sent reminder.
+        Guarantees the result is in the future.
 
         Args:
             current_run: Current run datetime
             days_interval: Days between reminders
 
         Returns:
-            Next occurrence datetime
+            Next occurrence datetime (always in the future)
         """
-        return current_run + timedelta(days=days_interval)
+        now = self.get_now()
+        next_run = current_run + timedelta(days=days_interval)
+
+        while next_run <= now:
+            next_run += timedelta(days=days_interval)
+
+        return next_run
 
     def add_hours(self, dt: datetime, hours: int) -> datetime:
         """
diff --git a/bot/utils/__pycache__/validators.cpython-312.pyc b/bot/utils/__pycache__/validators.cpython-312.pyc
new file mode 100644
index 0000000..30b0c5e
Binary files /dev/null and b/bot/utils/__pycache__/validators.cpython-312.pyc differ
diff --git a/bot/utils/validators.py b/bot/utils/validators.py
index 0482f29..b3e54a1 100644
--- a/bot/utils/validators.py
+++ b/bot/utils/validators.py
@@ -15,7 +15,9 @@ def validate_time_format(time_str: str) -> Optional[time]:
     Returns:
         time object if valid, None otherwise
     """
-    # Remove extra whitespace
+    if not time_str:
+        return None
+
     time_str = time_str.strip()
 
     # Check format with regex
@@ -47,6 +49,9 @@ def validate_days_interval(days_str: str) -> Optional[int]:
     Returns:
         Integer days if valid (>0 and <=365), None otherwise
     """
+    if not days_str:
+        return None
+
     try:
         days = int(days_str.strip())
         if 0 < days <= 365:  # Max 1 year