I think that joining study groups is very important, but i think that meeting once a week is prob. too much and a waste of time. (btw, i never had any study groups for undergrad either) Obviously, this kind of thing is very personal and works well for some and not so well for others. If you are gonna join a study group, make it with people you're not good friends with. Otherwise, study time can turn into socializing really quickly. Plus, is someone in the group is slacking off, it will be harder to confront them if they are a good friend. I think you should plan to meet with your study group after you have finished a major topic, def not more than that. The 2Ls I spoke with did not have study groups until finals time (and even then, they only met after everyone had done studying on their own). These 2Ls did, however, say that about 30% of their class did meet regularly in study groups.