When did age become an issue in the watch industry?

It could have been 2015, when Apple introduced its watch and millennials began to have a significant impact on luxury sales from the United States to China.

But it certainly was by 2016, when Mr Johann Rupert, chairman of the Richemont luxury group, whose brands include IWC Schaffhausen and Vacheron Constantin, announced that he wanted to "see less grey men" in top management.

Mr Rupert's statement turned out to be a prelude to sweeping changes in the group. Last month, he appointed Mr Jerome Lambert, 49, a former head of Jaeger-LeCoultre and Montblanc, to the newly revived position of chief executive officer of Richemont.

In May, along with the takeover of online retailer Yoox Net-a-Porter, Richemont continued the corporate shakeout of its specialist watchmakers division with the appointment that same month of Ms Catherine Renier, 43, as CEO of Jaeger-LeCoultre and, in June, of Mr Geoffroy Lefebvre, 41, as head of Baume & Mercier.

Ms Renier became the second female CEO at Richemont, following Ms Chabi Nouri, 44, who was named head of Piaget in April last year.

That was about the same time Mr Christoph Grainger-Herr, 40, took the helm at IWC, and Mr Louis Ferla, 43, became CEO of Vacheron Constantin.

But in an industry where chief executives traditionally have been male, Caucasian and well into their 50s, the trend towards younger executives has not been limited to Richemont houses.

In August, Kering announced that Mr Patrick Pruniaux, 46, CEO at Ulysse Nardin for the last year, was also taking the top job at Girard-Perregaux and its secondary brand JeanRichard - a new combined position that gave the former Apple executive responsibility for the group's Swiss luxury brands.

At LVMH Moet Hennessy Louis Vuitton, Mr Julien Tornare, 46, took the helm at Zenith in April last year.

Regardless of the individual visions for their brands, these new chief executives will change watches and watchmaking. They must or their brands could pay the price.

"In the luxury watch sector, the challenge today comes from the change of generational thinking among today's watch consumers, who are younger, better informed and more unpredictable," said Mr Oliver Muller, founder of consultancy firm LuxeConsult and former CEO of watch brand Laurent Ferrier.

The majority of those consumers are in China, which, when one combines the statistics for Hong Kong and China, is Switzerland's leading export market, according to the Federation of the Swiss Watch Industry.

Those Chinese buyers were the focus when Mr Tornare of Zenith gave a keynote address at the Arab Luxury World conference in May in Dubai.

"The real change in China in the last decade has been less the anti-corruption measures than the shift in generation," he said.

"The new generation of Chinese buyers is the biggest user of the Internet. They speak English, they study aboard, they are savvy and they won't buy at any price."

Elaborating on his comments in a telephone interview in June, Mr Tornare said: "To reach that generation, we need the right product at the right price, with real innovation that focuses on the soul of the mechanical watch."

With the proliferation of products that tell time - including connected watches and mobile phones - traditional luxury watchmakers have known for some time that they must figure out how to stand out in a crowded landscape.

"Luxury watch brands must tell a real story using a real strategy of communication that younger consumers find credible," Mr Muller said.

"It is not enough today for them to transfer their images from a glossy magazine onto social media."

Some of the new chief executives already have been making moves.

At Piaget, which boasts 144 years in business, telling Mr Muller's "real story" to today's younger clients has meant developing products that marry its heritage with modern expectations.

"Our clients are between 38 and 42," Ms Nouri said. "They are younger. They shop around and, while they may have less brand loyalty, they continue to buy watches as gifts to mark an occasion or as a means of self-expression."

Piaget's Possession watch collection, introduced in January at the Salon International de la Haute Horlogerie in Geneva, revisited the signature watches with hard-stone dials that it was known for in the late 1960s, with the added features of a rotating bezel and interchangeable straps to make the timepieces more of the moment.

"Heritage does not mean old," Ms Nouri said.

"Clients today want pieces that can be worn in different ways and adapted to different occasions."

Yet, Ms Nouri, who began her career at Cartier in 1998, said the effectiveness of a chief executive is less about her age as it is the ability to assess clients' expectations.

"Youth is a state of mind," she said. "Because the world moves so fast, our experience today is built differently, on moving grounds and within a shorter time frame, but it is just as robust."

Although, she added that "when you are in tune with your client because you are of the same generation, you can elevate those elements that are more relevant".

Pricing, for younger clients, certainly is a key factor.

It needs hardly be said that, once someone has bought an entry-level watch, the industry hope is that more expensive models will follow.

This month, with Mr Ferla as CEO, the 263-year-old Vacheron Constantin has introduced its Fiftysix collection, with an entry-level price of $16,900 in Singapore for the stainless steel automatic version.

While that may not seem affordable to some, it is significantly less than the house's six-figure gold models or million-dollar special pieces.

As the company website says, the hope is that the Fiftysix, whose name and design were inspired by a model, will "open up the world of fine watchmaking to every enthusiast".

Similarly, Jaeger-LeCoultre is offering its Polaris watches, based on its celebrated 1968 model, priced about $10,400 and $11,800 for an automatic.

Along with price, sales methods also are changing.

At IWC, Mr Grainger-Herr used his Instagram account for an exclusive offer of the house's Big Pilot Safari in titanium, priced at $20,700.

"When I look at communication channels and platforms five years ago and now, there is a dramatic evolution," he said in an e-mail. "I have only ever known working in a dynamic environment where change is the only constant."

While all those strategies can sell watches, innovation is where the new chief executives can be most disruptive, by bringing real mechanical originality to the market.

NEW YORK TIMES