I’m new to Beeminder but I’m someone who’s always used pomodoros or timers while studying to stay productive.
I had this problem same as you and I’d find myself spending a few mins doing something else and would feel like I’ve disregarded the timer and would cancel the whole session and restart.
The problem with this above method is that it is too strict and too rigid and leaves no breathing room.
Your 75% rule is a good solution to the issue but I can’t help but think eventually you’ll intentionally work only 75% of the time and use the 25% to do other things. Like it’ll become planned. That’s fine if it works for you. But I feel eventually, something like that would get to me and leave me unsatisfied.
What I do now instead is completely different. I use a timer to time not my focused study hours but instead the time of the day I intend to study and not relax or waste time - I call it the work hours. That means I plan it out that during this intended study time, I’ll not listen to audiobooks, game or go out. But other spontaneous things that you can’t plan or foresee like taking a phone call or replying to a text, I do while keeping the timer going. Today, I ended up having a discussion with family about something and I let it happen on the clock.
I have found this to improve my quality of work, leave me more satisfied and less exhausted by trying to forcefully concentrate. Often, the biggest drain is not focussing itself but forcing focus when not ideal. Think of it as a soldier doing his daily patrol that he has to cover like it’s a march, walking rigidly as opposed to the soldier walking casually, letting himself sway as he walks but still manages to cover the distance. Excuse the bad analogy.
Obviously, work time has to be longer than your targeted focus time.
This is basically like using the input based goals rather than output based to the input itself. Instead of saying “I’ll sit and focus for 6 hours today”, you’re saying “I’ll plan my day out and carve a period of 8 hours for work today. At this time, I’ll not do that, that, this and that.”
Maybe it will not work for all but does for me and probably will some of you.