Well, let's hope nobody drills a hole in the Moon (or blows the Moon up) in the next couple thousands of years, for the sake of those watches' usability.

> let's hope nobody drills a hole in the Moon

https://what-if.xkcd.com/46/ - while it deals more with the Earth (which has a more molten core), its still applicable. There's still molten material ( https://science.nasa.gov/moon/composition/ ) but it's a lot deeper.

> (or blows the Moon up)

As a classic Neal Stephenson (great world building, good plot... and it ends)... Seveneves starts with:

> THE MOON BLEW UP WITHOUT WARNING AND FOR NO APPARENT reason. It was waxing, only one day short of full. The time was 05:03:12 UTC. Later it would be designated A+0.0.0, or simply Zero.

... and given the book and the "what happens"... a watch surviving (much less keeping the phase of the moon) would be impressive.

There's also the Dr. Who take ("Spoilers") https://youtu.be/pHOnGSFzd3Y

It’s actually safe to do that, watch owners would be distracted by global cataclysms ;)

> Tides would be much smaller (…) But the movement of tides underpins the balance of ecosystems the world over, and an impact that widespread would cause global biological collapse across oceans and, in turn, the whole Earth.

https://www.popularmechanics.com/space/moon-mars/a43633761/b...