I also get many questions here about how much this or that particular watch is worth. A few comments about that in this post.
Rule #1: 3 things influence the value of a vintage watch: condition, condition and condition.
Rule #2: If you have a solid gold case, add $500 to the price (whatever it is determined to be). If it's encrusted in diamonds and is platinum, it doesn't much matter about the watch part anyway.
Rule #3: The watch is worth what a buyer will pay for it. There are price lists published, but they assume the watch has been serviced and is in running condition. Any buyer will have to deduct at least $100 US from the price list value if the watch has not been recently serviced. A watch seller will not give you more than 50% of the posted price in any case. Often eBay is the best way to get an idea of what your watch is worth.
Rule #4: Your antique watch is worth far less than you think. They are not rare, even if they are old. For instance Elgin made over 50 MILLION movements. They were built to last and be repaired so a lot of them are still around in various conditions of course. The average price for an 80 year old pocket watch is around $150 US. Of course how do you put a price on something your grandfather gave you when you were 7?
Rule #5: Watches stink as an investment. I bought an 1883 keywind Hampden in 1978 for about $100 US. It's value today? Maybe $175 US. I'm not going to retire on those types of returns. It's a great watch though.
So relax about value and just enjoy looking at Grandpa's Waltham or wearing dad's Bulova tank. Just make sure they are serviced that's all.