Learning a new topic takes you outside your intellectual comfort zone. Extrapolating from the spacing effect, the practice of overlearning a chunk of new material is an inefficient way to build memory. I notice, however, that overlearning feels comforting. It seems to establish a comfort zone in the new material. It makes me feel more confident that I've learned something new, like the material is becoming a part of me. And when I review the earlier material, I can approach the new material that builds on it with greater ease.
If you approach study with the idea that it's all about efficiently building a memory for the material, you might neglect the motivational aspects of study. What do you do to establish a comfort zone in your studies? Do you find that sense of a "comfort zone" motivating? What else do you do to enhance your motivation and engagement with your studies, even if it's not strictly optimal in the short term for building new memories?
I understand your point, and I for the most part agree. It is important to understand the basics.
What I was trying to say is.. If you did not get the basics from your first attempt to learn those, maybe try to approach them differently.
Look for a different textbook, ask someone who is not your current teacher, maybe look for popular explanation (if you are compltetly lost), or for more technical one (if original was not detailed enough), etc etc.
Try to learn the basics, but switch the approaches if you are stuck.
I feel like it might help with motivation too, as it should be more exciting than plain repetition.