Ideally, you should only work at learning something if you don't know it. Repetition wastes a lot of time to get that guarantee, but it would be much more effic

Ideally, you should only work at learning something if you don't know it. Repetition wastes a lot of time to get that guarantee, but it would be much more efficient to just recognize where you're weak and work at that. It's a rather lazy meta-learning strategy to just throw spaghetti at the wall until everything sticks. I think it's fine if someone chooses to learn this way, but it's unfair to expect all the other students to waste their time---I really hated when math teachers assigned 30 problems of homework, because I didn't need 30 of the same problem to know how to solve it, and almost no one does. Really, you only need repetition for a small percent of the content, it's just what "clicks" for each person is different. I appreciated what my high school chemistry teacher did instead: all problem sets were optional, but there were recommended problems. Then, we had tests every two weeks which we were allowed to retake, but only once we solved the problems. That way, we quickly see if we're missing any knowledge and are forced to learn it for a good grade.