How long to LOOK like you know what you're doing?
Say an actor was playing the role of a boxer. Starting from scratch, how long would it take to get the aesthetics of boxing down? How long would it take for the actor to be able to at least somewhat convincingly fake it? Hilary Swank didn't look bad at all in 'Million Dollar Baby', and Will Smith didn't look bad in 'Ali'. Not sure how much camera angles and editing had to do with that, though.