it depends on your school's exam schedule. if you have exam blocks in which you have 3-5 exams in one week while the other three weeks of the month you don't have any, then that may be very different than if you have one exam every week. if you have blocks then you don't really have to do all that much, just keep up and prepare for quizzes during the first two weeks, then the week before and during exams you have to put in much more time. I'd say during the off weeks you'd put in about 0-1 hr/night and week before exams probably 1-2 hr/night and then on the two weekends before, put in full days. but, yes, there is definitely time to not be studying.