Hello PF, I am encountering a problem in these last years. I've always been interested in reading science books and textbooks but I have encountered the problem which is I don't feel that it is helpful to me because I will retake the subject in class. For example I was reading about relativity and then we studied it in class and I felt that all my efforts and the time I spent studying it was useless that's because everyone was on the same foot as I am though I have done more work and spent more time studying. But at the same time i cannot just wait for class to study my favourite subjects. For example now I want to study differential geometry but I know that next year I will be taking the same subject I don't want to waste my time studying this year but I can not be patient enough to wait for next year.