eh, with math and the like, repetition (well, good repetition) helps with retention of problem solving strategies and then allows you to be well grounded to keep advancing. I really disliked posting up in the library for long periods of time, practically up to 6+ hours, just busting out math problems, but in the end, it was beneficial.
I'm in a structures class and the instructor doesn't give us shit in the way of problems (only a couple a week), so the concepts are just not sticking and I have no goddamn clue what to do on the midterm tomorrow. So, as of right now, I'll take some repetitious bullshit and having some knowledge over just being bewildered. It isn't so bad!