Flipper rebuild was the first thing I did as a newbie on my first game, it played just and looked fine to me, when the new parts arrived I realised how bad the ones in my game were. Once the flippers were rebuilt I felt a real sense of achievement, and found the rebuilding as much fun as playing. Three years later I am buying junked machines and rebuilding them, you got to start somewhere, and like it or not machines will break down and you have got to learn to fix them yourself unless you are Richie Rich and call at tech every time something goes wrong.
Just do I say if break something then fix that also there is lots of help on this forum.