Practice wrenching on your own bike. Owning 2 bikes is useful because at least one can be raided for parts at any given time. You'll know she loves you if she offers to let you ride her bike. Never argue with an 18-wheeler. Never be ashamed to unlearn an old habit.
Maintenance is as much art as it is science.
A good long ride can clear your mind, restore your faith, and use up a lot of gasoline. If the countryside seems boring, stop, get off your bike, and go sit in by the ditch long enough to appreciate what was there before the asphalt came. If you ride like there's no tomorrow -there won't be. Gray-haired bikers don't get that way from pure luck.