I've kept vehicles 10-15 years by doing my own maintenance, even when those vehicles weren't purchased new by me. I've learned most of what I know by doing the research, asking questions, and "figuring it out" rather than in a classroom. I'm not a mechanic, but I can fix and diagnose many things, although I've never rebuilt an engine or transmission.

My experience is mostly with GM vehicles, but I do have a Chrysler that I've done some work on and it doesn't seem too significantly different.