The tool that might cost a lot now but pay for itself in the long term is a truing stand. If you think you will be riding bikes for the rest of your life, get a truing stand now. This is one tool I wish I would have bought 20 years ago. I have had one for four years (due to the feedback from this forum) and it is awesome.

I am guessing a good portion of the riders on this forum have anywhere from a slight to moderate wobble in either wheel. Untrue wheels are slow, uncomfortable and just suck!!