If another magician asks me where I learn most of my magic I would tell them it is a wide variety of resources. Books, Dvds, my local club, lecture notes, jam sessions with other magicians and mostly me mentor who I pay for lessons hourly.
I really never have laymen asks "where" I learned something but they will normally ask, "How long does it take to be able to do that?" or "Do you practice a lot?" Things of this nature.