Someone told me he makes more money from retouching wedding photo's than he does from actually taking them, because over the years he gets requests to remove xyz from the shots as they fall out of favour.
He said it used to be difficult to do well in Photoshop and was labour intensive until he hit on a brilliant idea, he now takes a shot of the background before moving the punters into the frame, thus he simply needs to cut a section from his background shot and paste it over the rogue guests as required and he still gets paid handsomely for doing it.