When I got my first job out of college I thought I could finaly afford to have my work done by a shop. Not only was it too expensive but the work was also incompetent. I learned three lessons:
1- Find a car you enjoy working on
2- Do everything you reasonably can yourself (all those little repairs and maintainence add up to huge numbers if you have them done)
3- Find a really good specialist for when you can't
Its obvious advice but I'm embarassed how long it took me to figure it out.