As a first year CompSci student I find this method works remarkably well for me. Workloads are most likely different where you are but I find I'm able to complete most (often not all) of my schoolwork within this time constraint. It's all about productivity. I never even realized how much time I spend on HN or reddit or whatnot when I still have work to do. I have been following this sort of method for a month now although I find I have to break my rules almost every week, I mostly manage to get everything done between 8 and 5. The author makes a good point on sleep too, I can't stress enough how important it is to get a good nights sleep for productivity!