I'm new to the cycling world, but I'm quickly realizing it isn't that hard working on the bike myself.
I actually know fairly little about cars too but insist on taking a crack at just about everything maintenance wise with my Jeep and my wife's Volvo.
I think that in addition to saving money, it is nice to know how things work. When something isn't shifting right I can more easily identify what is happening now that I know how to adjust the derailleurs.