I repair, rebuild and build watches and clocks as a hobby. It is a fascinating subject.
Mostly I work with ETA and Valjoux movements and especially chronographs, although I find almost no one that owns one actually uses, or even knows how to use, the chronograph function. As has been noted, these are the base movements of many Breitling, Tudor, Rolex, and other high end watches.
This is a "pandemic project" watch I built- a Russian Poljot chronograph (previously posted)
