Parts rarely fail on watches from the 50's on, especially the better made watches that are sealed. Even those that arn't sealed very well, the parts seem to last.

If a part does fail, it's usually the old blue steel mainsprings.

They can be replaced with modern White-Alloy springs. (That is just a brand name.)

Watches are my thing. I don't know why I like them so much, but do.

Servicing does take awhile to learn though. That whole 10,000 hrs probally. Servicing a watch does not take that long to learn. I'm talking about making parts with a Jeweler's lathe. And getting to the point where you know those parts well enough to visualize exactly what's wrong with a timepiece by looking at it.

If you did learn to clean/oil your mechanical watch, it's something that will be passed down to loved ones.

Oh yea, Service a mechanical watch when it stops keeping good time. That is unless you take it in the water.

I know a watchmaker who told his father he needed to Service his gifted wristwatch. His father got it 30 years ago as a present, and just wore it daily. The watchmaker was expecting dried up oil, but to his astonishment, the oil was still there. It was hermetically sealed. Oils do breakdown, but he couldn't find any damage to parts using a 40x stereoscope.