Hello there! New to the forum, this being my first post. I have always admired vintage watches, particularly Art Deco era ones and so recently bought five on eBay, four Elgins and a Bulova. My question relates to one of the Elgins which sets and runs well, loses about five minutes a day if you wear it, but if wound and left on the table it will often stop after a few hours... sometimes. Is it likely to be due to worn parts inside, a balance wheel issue or similar? I called a couple of watchmakers in town and basically got answers like "bring it in we charge $50 - $300 for a clean and service". Not sure I want to commit to spending $300 on a $50 eBay find which may have deeper issues, I haven't contacted the seller yet either, any advise for a vintage watch newby?