My watch was running fast, so I broke it.
A smartphone filled in but from time to time I would think about getting my watch running again. I would prefer to buy a decent digital watch to paying for a professional repair, and figured that a shop would just swap out the movement anyway.
So I hunted around and found a new replacement movement for $34 from a Greek seller.
This would be like replacing a car engine because of a bent spark plug, but the nice thing about tiny hobbies is that they sometimes have tiny prices.
The movement came with an adapter ring and some tiny screws to secure the movement in the case. The smallest tool in my cheapo "precision" screwdriver set looked like it would be far too blunt, so I filed the tip of a matchstick size screwdriver from an eyeglass repair kit down to the size of the screw head.
Giant eyeglass bolt for scale; 5 mm square background.
I had never removed the movement before, and the first step was to remove the crown. A spec sheet assisted in locating a release button, pressed with a green toothpick.
The mounting screws holding the movement in place were even tinier, but getting them loose was far easier than putting them back in place would be.
As described on many forums, these parts have rounding error for mass and one managed to leap to the floor but was recovered without employing magnetism.
I put the movement in a plastic bag to block dust and removed the hands by levering on them with tiny screwdrivers from outside the bag, leaving only minor damage on the dial. The dial transferred easily to the new movement, and the green toothpick assisted with getting the hands reconnected.
After an excruciating bout of fussing with the mounting screws, everything was in place and I put on the case back and gave it a test wind. To great satisfaction the second hand started turning and everything looked good.
But I've learned that there is always at least one goof on any project, and I hadn't lost any parts yet. The watch stopped after a few hours, and I could only get it going again by adjusting the time. It stopped again, and I noticed that the hour hand had brushed up against the second hand and gotten stuck. Somehow I had bent the hands while brutalizing them with toothpick and screwdrivers so their orbits intersected.
I waited a few days until my patience reserves were restored and went back in. A little nudge with the toothpick was enough to get the second hand back in line. The second time with the mounting screws went better after I learned to get the screw started with the tab rotated to the side, then turn it into position as the screw tightens down.
It's a fun hobby that fits in a desk drawer.