The first part of our semester we were basically in class for ~5 hours a day except for Friday, which was ~3 hours (so ~23 hours/week ). It wasn't a continuous 5 (or 3) hours at a time, there were breaks/gaps built in. You can have as much or as little free time as you want. It's all about your personal balance of school and leisure. You need to emphasize school but you also need to make time for fun stuff to maintain your sanity and mental health. Ultimately, this is graduate school, if you think you're just going to skate by doing the bare minimum, you're not going to make it. You're going to have read a lot of material from textbooks and/or lectures on top of practicing your hand skills in lab. Especially with PBL, I "aim" for note taking 1 chapter and then reading a separate chapter's already completed notes. On the weekends, I try to give myself a "free" day then a study day, but that's not always the case.