Exams, assignments, and the study time set aside for each. One place.
Time management and efficiency are two of the biggest contributors to a good grade. Nobody teaches either one.
A calendar full of dates with no preparation attached is just a list of things to worry about.
Add a date. Say when you are free. I build the preparation, slot it into the time you have, and remind you before it matters.
That’s the whole maintenance. You add dates. Everything else schedules itself.