When you have a vintage watch, the question that without a doubt you will keep asking yourself is: when was my watch made? Now, is dating a watch possible? Sometimes it is, sometimes it isn’t. Anyway, it’s very useful as a collector to know how to date a watch.
The first thing to check is serial number charts. Sometimes they’re official resources, sometimes they are compiled by brand aficionados. They attempt to combine all the bits of knowledge scattered out there into one, more or less accurate resource.