Ive been in a boarding house for 2 years so it always seems to be a comp...my best is 20 and I had to it in 15 mins because I was late for school. Not a good thing... my stomach was in pain for a while...
As for study, I do 9 hours.. I get up early cause im a morning person and i cant study at night...get to distracted by tv so i work most of the day...
You just have to find a number that suites you, that means creating a timetable that bases itself around times when u really dont do much, and create time for period when u dont want to be working. For instance, I have from 1:30 - 3:30 off because i love the hottest part of the day, and so i have a swim and stuff around outside...
Cheers