I'm a bit wary when people say they're revising now, but maybe my learning style is very different... If I don't have homework on a week night I will probably do an hours worth or two of past papers or revision. I'll mostly be spamming past papers... I usually take Friday night off, as well as the weekends though. During exam leave and Easter I'll work 7 days a week though
10-15 minute breaks are good, I usually have one after an hour of working.
Also, I just heard about contradiction marks in A level mark schemes, what the actual hell?!