LONDON : The late McLaren boss Teddy Mayer liked to compare Formula One drivers to interchangeable light-bulbs, declaring "you plug them in and they do the job", and nowadays the same might be said for team principals.

The season kicks off in Bahrain next week with four of the 10 teams under new management since the end of the last campaign.

Aston Martin's Mike Krack, who was appointed in January last year, is now the fifth longest-serving principal in the paddock after taking charge a matter of days before Otmar Szafnauer arrived at Alpine.

Ferrari, presided over by founder Enzo for more than 40 years until his death in 1988, have Frederic Vasseur freshly installed at Maranello as their fifth principal in under a decade.

The Frenchman is on his third different team, after stints at Sauber and Renault.

Andreas Seidl has moved from McLaren to replace Vasseur at Sauber, the Swiss company which runs the Alfa Romeo team, with Alessandro Alunni Bravo effectively the acting principal reporting to him.

Former Ferrari engineer Andrea Stella has taken the principal role at McLaren in an internal promotion while James Vowles completed the merry-go-round by moving from a strategy role at Mercedes to boss of Williams.

"I am counting the days," joked Krack, a former Sauber engineer and BMW Motorsport boss, at the launch of the team's new car when his 'longevity' was mentioned.

"I was surprised about how these things went, especially in that very short period of time," he added of the winter reshuffle.

"It shows also that the role of the team principal is maybe sometimes also a bit over-rated because if you can change it so quickly and there is no big impact, it tells also something.

"On the other hand, I think consistency and stability is very, very important."

PIRANHA CLUB

There was a time when principals were founders - men such as Frank Williams, Colin Chapman at Lotus and Ken Tyrrell whose personalities formed the team's image.

It would have been unheard of for them to switch loyalties in what was known as the 'Piranha Club' of bosses but those days are long gone.

With the exception of Toto Wolff, who owns a third of Mercedes F1, the current crop are managers reporting to someone else and, like their counterparts in soccer, dependent on results.

Vasseur's bosses are Ferrari chief executive Benedetto Vigna and chairman John Elkann.

Canadian billionaire Lawrence Stroll really calls the shots at Aston Martin, Frenchman Laurent Rossi is the CEO of Renault-owned Alpine and American Zak Brown the true leader of McLaren Racing.

Sauber, with Swedish billionaire Finn Rausing as chairman of the board, will become the Audi works team from 2026.

"It is about managing an organisation with a certain style and it seems like you can give these jobs to anyone or to someone from another team," said Krack.

"I'm surprised about the quick releases that we have seen, this I would not have expected.

"But other than that we must not forget that F1 teams have developed into big organisations where the owners are not any more the team principals... some have engineers as team principals, some have more an old-fashioned rule."

Red Bull's Christian Horner, who arrived with the energy drink company in 2005, is the longest serving principal, followed by Red Bull-owned AlphaTauri's Franz Tost, Wolff and Haas's Guenther Steiner, who reports to team owner Gene Haas.

They are managers but also television personalities, as much as the drivers even, with their rivalries played out for a new generation of fans through the Netflix docu-series 'Drive to Survive'.