For me as a collector and self proclaimed treasure hunter my views on things that are “Rare” and hard to find (I think they go together) vs Expensive and limited editions are two totally different things. Also as a full disclosure I dont deal in high end watches as my primary collection, so Rolex, Patek, Vacheron are not watches that I am in the market for. My collection starts at budget to mid end such as Omega, Tudor, Seiko etc…
Rare watches by my standards is a watch that no matter how much you look there are only a few examples that can be found easily. This doesn’t necessarily mean that it is expensive or of high quality, it is just hard to find which in turn makes it a rare item. there are many examples in my collection where I have found a watch that literally none of the collectors I deal with have ever seen before (and some of them have been doing it 40+ years) and no matter how hard I look on the internet or tracking through Ebay have never seen the same watch again or maybe once or twice in a blue moon.
But you also need to consider how many watches you look at in a day, week, year etc.., if you are like me I probably shift through hundreds of watches a week on Ebay, at flea markets etc and have special filters and alerts for key worded items as they get posted on ebay.. so when I see a rare watch I believe it is really rare or hard to find I classify it as a rare watch.
One example of a rare watch is one I pulled out of a watchmakers junk watch drawer for $5, it was a Phasar Bull Head Quartz watch, probably one of a kind (pictured below), although it is probably not worth much I believe there are very few out there if any at all. Compare that to an Omega Speedmaster pre Moon with a 861 or a 321 movement in it. Many people consider this a rare watch but yet you can find them on sale on ebay, chrono24, etc.. I agree there are limited number in the market and most likely because collectors do not want to give them up but does that make them more rare then the Phasar above?
Another example of a rare watch would be an Omega Seamaster I picked up recently, the model itself and the movement are not rare by any standards (the movement was an Omega 286) but the dial was unique and something I have not seen very many of if at all on an omega watch. After purchasing I did a couple days of searching online and came back with nothing (there where a couple multi toned dials but nothing with this configuration)
So how about expensive watches that many people consider rare such as the Rolex Daytona they have a lineup of buyers waiting to purchase them because Rolex only wants to produce a limited number a year to keep the prices and interest high, does this make them Rare? to me it doesn’t make it rare because its an artificially created vacuum of demand but if you have ever spoken to someone that waited a year just to buy one they sing a different tune.
I guess different people classify rare in their own perspective.