I'm a second year and I feel that I've developed my study habits at this point.
I don't attend any class.
However, PCOM records all of the lectures that are available for streaming usually by the same afternoon or latest by the night. I almost always listen to any clinical lectures we get while physio, path, micro, and pharm lectures I don't bother listening to. Reason is that Guyton's, Robbins, CMMRS, and Katzung are great resources that I read in to for a certain topic and look over the powerpoint.
My system is so efficient that I only end up spending same amount of time going over stuff and taking notes as the amount of time that the lectures run for. This means for a 4 hour lecture day, I end up spending about 4-5 hours that same day and I've pretty much grasped the concepts and memorized key features.
Obviously, over the weekend I go over all the material once memorizing more and more detail.
But you get the idea that I'm not slaving away 8 hours a day and 12 hours a day on weekends.
For downtime, I take 10-15 minutes break every hour and usually after 2-3 hours of studying, I end up taking an hour break. Watch TV, food, or gym.
This system has worked great for me so far. I'm probably in top quartile of my class and I feel that I'm understanding the material well. Above all, I keep my sanity!
Ultimately though, focus on developing YOUR OWN study habits. Don't worry about the guy who spends 10 hours a day studying and certainly don't worry about the guy who crams a week before the exam.
If your school records lectures, then I'd suggest you stop going to lectures.