Have you ever spent three hours on "OK, I'll just play one more map"?
Then this mod is for you. And of course, it is for me

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Source
What is Pomodoro?
https://en.wikipedia.org/wiki/Pomodoro_Technique
Pomodoro is 25-minute time period.
How does it work?
1. When you start the game, the pomodoro timer is set (by default 25 minutes).
2. You play the game.
3. After 25 minutes, annoying messages appear that suggest you to take a break.
4. You pause the game, relax, walk, stretch, etc. for 5 minutes (by default).
5. Then you play the game again.
6. Every 4 pomodoros instead of usual break there is a long break (by default 15 minutes).
Features:
- configurable durations for pomodoro and breaks (Options->Pomodoro Options);
- timer works even when game is paused (or menu is opened);
- it is possible to force pomodoro, or break, or long break;
- configurable keys (Options->Pomodoro Options);
- mod doesn't interfere with gameplay. When time is out only messages appear;
- savefile compatible! It means that you can load pomodoro.pk3 with any existing saved game.
Spoiler: Screenshots:This mod was a part of m8f's toolbox.