Is it better to study once but perfect or many times not perfect?

Study until you think you got it all memorized and have someone like a friend or family member ask you the questions on the exam a few times until you got the right an than go to bed get at least 6 hours of sleep because if you stay up all night studying your body will go into stress mood an your brain will freak out and you will have short term memory loss an you will forget what you just learned so try to get lots of sleep after you study