When I was a kid, my dad had a late-1960s flip alarm #clock that became #unreliable, losing random amounts of time daily. He replaced it with a newish-at-the-time LED clock.
I went to the basement, took the flip clock apart, figured out how it worked, moved every moving part in it, and put it back together. Basically knocking the accumulated dust out of the mechanism "fixed" it.
I've been hooked on #fixing#things ever since. It's great.