It depends. I have a thick skull, even with the best teacher I probably wouldn't "understood" the advices until my own intuition about things was matching them. I took years to learn some stuff, that I could have found in a one afternoon if I asked the right questions. But I couldn't. Now I know that I am capable of finding them, and that I can also communicate to share point of views and ideas. Also, teachers could be wrong too. There's a lot of stuff in my understanding of music that I find no trace of in theory (except for the "swing it" tag on a score).