The ability to concentrate and to use time well is everything.
-- Lee Iococca
In any study, concentration and focus is the key to success. If you are able to focus and use your time well, you do not need to repeat your work.
If you do not exercise your ability to concentrate, or to use time well in class, you are unable to do the homework without the help of tuition teacher.
If the work you do is not directly from you, it may not be with you in your comprehensive mind or long term memory even if you have done it. All learning will be a painful process of recall and confusion!
On the contrary, if you are able to listen in class with full concentration and understand the lesson, you do not need to attend remedial class or have tuition after classroom hours.
You will use your time to build something new upon something you know well.
If your foundation is good and stable, you can excel with new acquisitions of knowledge, and learning become interesting and stimulating.
With that, your learning become part of you!
Learning something new is not difficult and you will always find it joyful to add new understanding!