It's funny because if you were to ask me, I'd tell you I was a self taught turner, and I mostly am from books, DVDs, demos and many hours spent at the lathe but, in my early days I had a day with John Berkeley and spent a day playing with boxes, threads and bone work. I have also spent a lot of time with Les Thorne, Gary Rance and Stuart Mortimer on a less formal basis. I am lucky enough to call all of these people friends and I would possibly go so far as to say Gary is something of a mentor, even if he doesn't realise it!
I think it's less about tuition as such, and more about having a thirst for knowledge, so while I don't have formal tuition these days (that's not to say I won't, just I don't have any plans at the moment), I do still attend demos, seminars and read books and magazines on the subject. As you progress there is less new information to learn but by watching demos and reading magazines etc, every so often a little gem will appear which can be hugely helpful.
Cheers
Richard