Try building an aeroplane or two through the PFA or BMAA schemes and you do kinda learn a thing or two about maintainance issues.
In my case I started rebuilding trial bike engines as a kid, then moved on to cars and tractors and worked as an "unqualified" agricultural engineer for a couple of years. I know my way around engines and latterly airframes ... shame I can't loose the habit of using baler twine at every opportunity though
I can't believe anybody interested in aircraft, cars, bikes or whatever doesn't take some interest in how they work
SS