I’ve lost my stomach for fixing up well worn 321 Speedmasters.
Even after everything external is squared away, you still have a movement that has wear, maybe substantial wear, throughout it. These watches wind up going back to the watchmaker repeatedly, because something else keeps breaking or falling out of adjustment.
The watches that have given me the least grief are the ones with little evidence of wear or use. For the obvious reason, those movements work like (almost) brand new. Like most of us here, my favorite discovery in a new acquisition is that there are no watchmaker’s service marks and the movement looks pristine.
I used to think I could get a bargain by getting a tired watch and reviving it. Often, between time, aggravation and money, I haven’t saved nearly as much as I’d originally expected. And even if all went well, I still had a worn out Speedmaster that I knew was an assembly of mine, not the factory.