...that hadn't been serviced since 1982.

That's a little excessive for a service interval to say the least. The customer explained that the watch began to run "very fast and erratically" and then just stopped.

The "fast and erratic" part is from the balance losing amplitude as the lubricant and bearing surfaces failed.

Needless to say some parts will be replaced at a fairly high cost - luckily the watch is a Rolex so parts are available for the calibre.

Here's a link to some interesting reading concerning the dreaded service interval. And why it needs to be done.
http://home.watchprosite.com/show-nblog.post/ti-432276/

Remember - on this forum these are vintage watches with limited parts availability that we are usually talking about. A cared for watch will last practically forever.

Cheers

Hear Hear Brother! or as we used to say in the 70's... What he said!