The Knights of the Round Table quested in search of the Holy Grail. Ponce de León scoured Florida for the Fountain of Youth. Alchemists sought the philosopher’s stone that would transmute base metal into gold. And for the last decade and a half marketing people have been obsessed with reaching millennials.

I am no marketing expert, but so relentless has the bombardment of demographic pseudo-science been (my favorite was the introduction that I received into the mysteries of something called “millennial pink”) that I believe we have been overcomplicating things.

Zendaya, an avid watch collector and a millennial, is a fan of the relaunched Panthère de Cartier.

The surprising but, when you think about it, logical answer that the watch industry has arrived at is that millennials like millennial watches, by which I mean not something dreamed up by an unhappy collusion of A.I. and focus groups, but stuff that, like millennials themselves, first saw the light of day during the 1980s.

One of the earliest signs of the phenomenon came in 2017, when Cartier reissued its Panthère. The Panthère was launched in 1983, and as far as I was concerned it could have stayed there. I love old Cartier watches—they’re the closest thing I have to a passion—but for the Panthère I make an exception. So it is just as well that Cyrille Vigneron is the C.E.O. of Cartier and not I, as he scored a bull’s-eye with the Panthère. It was a smash with twenty- and thirtysomethings who remembered their mothers wearing it.

A neo-vintage version of the Panthère de Cartier in pink gold and enamel.

Vigneron repeated the same success a year later with the Santos de Cartier. First launched in 1978, it was nonetheless an emblematic 80s watch, having been worn by Michael Douglas in Wall Street. Like the Panthère, it was almost identical to the original, and it heralded the return to watchmaking relevance of Cartier after more than a decade spent chasing the chimerical market for technical and complicated watches.

The term “neo-vintage” was initially used to describe this sort of watch: new in terms of production but vintage in terms of styling. It has since developed into a description of a period of watchmaking that had, until recently, gone unrecognized and under-appreciated.

Madonna wears an original Panthère de Cartier in 1987, alongside her then husband, Sean Penn.

Unlike the temporally demarcated furniture styles of 18th-century France—Louis XV, Louis XVI, the Directoire, and so on—there are no absolute rules about what makes a vintage watch, but the cutoff date is usually understood to be the mid-1970s, when battery-powered timepieces threatened mechanical watchmaking with extinction. Contemporary watchmaking is generally taken to mean watches made in the 21st century.

New in terms of production but vintage in terms of styling.

By the beginning of this decade, soaring prices had put vintage “grail” watches, such as the Patek 2499, beyond the reach of all but the richest collectors. Meanwhile, waiting lists for desirable steel sports models stretched years into the future. Collectors began to look elsewhere, and that elsewhere needed nomenclature to unify and dignify a period of interesting, but heterogeneous, production.

A holy grail of watch collecting—the Patek Philippe 2499—regularly sells for more than $1 million.

“We first became conscious of the term ‘neo-vintage’ entering the popular vernacular some five or six years ago,” recalls Silas Walton, C.E.O. of the rare-watch sales platform A Collected Man. “Colleagues and clients alike began to draw comparisons between seemingly different things. Mid-90s Roger Dubuis chronographs; late-80s Daniel Roth; late-70s Audemars Piguet Perpetual Calendars, with their mid-80s Patek equivalents.

“From the aesthetics, production techniques, materials, and context in which they were created, watches that belong to this group are the result of mixed influences. They were long discarded by collectors, precisely because they fell between the cracks. To many, they either lacked the charm of older pieces or the excitement of new releases.”

Not anymore, as Florida-based vintage-watch dealer Eric Wind explains. At 37, Wind is a millennial with an enviable client list of millennials, including N.B.A. player Kevin Love, actor Ronny Chieng, and comedian Jimmy O. Yang. Wind also helped source the Rolex Daytona that was such an important part of the plot of the film Crazy Rich Asians. In other words, he is as sensitive to popular culture as he is to shifts in the watch market.

In Crazy Rich Asians, the Rolex Daytona plays a starring role.

Taking Patek Philippe’s renowned perpetual-calendar chronograph, the Reference 3970, as an example, Wind can show how dramatic the rises in interest and prices have been. The 3970 was a great watch that remained in production from the mid-80s to the early 21st century and for most of the last 20 years or so has been a sleeper. “About three years ago, I sold a second-series 3970 for $65,000. If I had it today, it would be $150,000. I wish I had held on to it a little longer.” And Wind has seen some examples with “special characteristics,” such as rare dial colors, hitting between $300,000 and $400,000.

“I think part of it is similar to what we see in car collecting, where the old adage is that people want to collect the cars that were on their wall posters as a kid. So, over the last 10 years, you saw 1980s supercars becoming more valuable. It is like that with 1990s watches: people who walked past a Rolex or Patek dealer 25 years ago want to get the watches they aspired to own 25 years ago.”

But if you have missed the 3970 train, as I have, the beauty of neo-vintage is that it is a catholic church. For instance, Tim Green, the commercial director of watch dealer Subdial, suggests that 1990s and early-aughts Chopards are offering good value. “Their L.U.C dress watches, with the stunning 1.96-caliber movement, have probably now found their new price point, at between £18,000 and £25,000 [$24,000–30,000]; the finishing is exceptional, with dials to die for, and the size that sits perfectly on your wrist; a few years ago, they sat unsold for under £5,000 [$6,000].”

Moreover, the neo-vintage focus on recondite rather than canonical pieces has other tangential benefits, as Green explains. “Neo-vintage watches are not so popular that your casual watch thief can spot a good one from 50 feet, or on a crowded tube train. So, us passionate collectors who enjoy wearing fine watchmaking, without simultaneously fearing for our lives, get to ‘flex’ in a way that only another W.I.S.—Watch Idiot Savant—would recognize.”

Nicholas Foulkes, the author of more than 20 books on the arts and history, is a London-based writer and editor