Three decades ago, even the canniest auction houses could not have predicted that watch-only auctions would turn into big business, let alone social events.

It was only in the late 1980s and early 1990s that collecting spread beyond a core of fusty connoisseurs and a network of museums.

In 1974, Antiquorum was founded in Geneva as an auction house dealing only in watches, clocks and related jewellery. It created the template by which watch auctions are conducted, especially the detailed catalogues that let the buyers know precisely what they were bidding for, from condition to provenance.

By 2005, Antiquorum’s annual turnover passed the $100m mark; the company typically conducts 10 auctions a year, held in New York, Hong Kong and Geneva, so the average is an impressive $10m from each auction. No wine, no paintings, no vintage Ferraris, no ex-Jimi Hendrix Fender Stratocasters. Just watches.

In the 1990s, the best place to find a wealthy bachelor in Manhattan was at any watch auction rife with Rolexes and Patek Philippes

That’s just one house. Christie’s, too, has an enviable reputation for securing highly desirable pieces, while Dr Crott and Henry’s in Germany hold watch-only auctions, as do many smaller companies. And it seems there are enough buyers to support all of them.

So who is augmenting the old-school collectors and museums, lending watch auctions the glamour and excitement seen during the vintage car craze of the 1990s?

Auction expert and FT contributor Simon de Burton thinks increased media coverage of wristwatches in general and wristwatch auctions in particular has brought a new breed of buyer to the salerooms.

He says: “Where horological auctions were once attended mainly by dealers and specialist collectors, they now attract a younger crowd on the lookout for late-model wristwatches which they hope to snap up at a worthwhile discount over retail.”

Unsold stock, now an important component of the auction scene, has enabled buyers to acquire watches for as much as 50 per cent below the retail price.

Quite where all the unsold watches come from is never made clear – bankrupt stock from stores that have closed, overstocks from too-optimistic manufacturers. However, the opportunities these bargains present are far more attractive than purchasing the same pieces on-line: buyers get to examine before bidding and know they are not buying fakes.

For newcomers, it is one of the most cost-effective ways to build a collection – provided they exercise common sense akin to knowing when to stop feeding coins into a slot machine in Las Vegas.

Mr de Burton thinks many are creating “watch wardrobes” and some use the salerooms to refine their collections. This explains the presence of so many almost new pieces. If a buyer fell out of love with a watch after a few months, putting it in auction gives a better chance of recovering most of the purchase price.

Auctions are safe places to buy because reputations are at stake. Cartels are frowned upon with much severity, so the packs of dealers attending the auctions tend to be working on their own, and the visibility of watch auctions is too great to permit shenanigans.

Mr de Burton notes that: “Less than a decade ago, the average wristwatch auction would be attended by no more than a few dozen people. Now salerooms are often packed to capacity, especially for landmark sales such as that of the Mondani Rolex collection recently staged by Antiquorum.

The dealers, high-end collectors and museum representatives are still in there looking for the best pieces and, invariably, these are the people who still pay the top prices – but they no longer rule the roost in the way that they used to.”

Regular attendance at auctions used to provide buyers with the knowledge of who not to bid against, with some deep-pocketed dealers specialising in chronographs or military watches or complications. It was once easy to spot trade bidders, privateers, major collectors and buyers for museums.

Now the auction crowds are so eclectic it is hard to tell until the hammer drops. But if a Patek Philippe, a Breguet, a Panerai or a Rolex sets a record, it is a safe bet it is destined for that brand’s museum.

One unexpected by-product of the increase in the appeal of watch auctions was as unforeseen as the growth in turnover. A veteran collector told the FT that, in the 1990s, the best place to find a wealthy bachelor in Manhattan was at any watch auction rife with Rolexes and Patek Philippes.

One wonders how the scriptwriters for Sex & The City missed that one.