It's interesting, though, in that it's so different from the way that other vintage items are valued (well, to my limited knowledge, at least). With other vintage items - furniture, books, crockery/glassware, pictures and so on - damage and wear is viewed negatively. It reduces the value of the vintage item. In other words, the more pristine the vintage item, the higher the value. However, when it comes to some watches, people are willing to pay considerably more for watches with visible wear-and-tear - it enhances the value, rather than reducing it!
Another 20 cents worth. When I did my Masters I did an internship at the NMA. The curators their valued the wear and tear and scarification of an object over time as it provided clues to the objects narrative and journey. These become the narrative speach of an object as it circulates through the commodity market, community and also offers insight into the individuals it encountered on its journey. Its manufacture, individual ownership, where it was repaired how many times it was exchanged. The provenance speaks volumes about an object and its inscription tells the tale of its circulation as both a commodity with a monetary value and item of cultural exchange.