I just fixed an expensive vacuum cleaner that was throwing belts. I glued a small spacer on the drive motor shaft that stopped the belt from wandering. Cost - zero. Time - 10 minutes. A small victory in the war against things that are aggravating.
A few months back I had an expensive GPS harness die. Without the harness I had to run it on batteries only and it would be tough to change them out while flying. The tiny connectors were corroded in place. after finally digging them out I replaced them with tiny springs from watch band pins. Cost - zero. Time - a few hours of fussing.
Also had a microphone die on an old headset intercom system. It was a dedicated system that matched headsets to an intercom. One of the microphones died. I bought a $4 handheld microphone and cut the actual microphone out and glued it to the unit. Works great.
So pat yourself on the back and post your success stories here.