I have adhd and have lots of things that I went through and want to share. One thing I learn is that ssetting 15 minutes or some time never works to me. I rather count time how much I studied. I use toggl timer (app/online available) to record how much I have studied on a particular subject or material. I start the timer when I really start studying and turn off when my brain deviates. One session(?) Lasts 10-15 minutes on average. For example, I need net 40 hours to receive b on a subject (exam prep) then I just kept studying till I reach that hours. I let myself take a break as my brain wants to. I don’t reach those hours in one day rather a week or two weeks. It works for me well…. Cuz setting 5 minutes break drives my brain crazy. Tt
Hope that it helps. Welcome to ask more questions if you want my advice.