For Lewis Hamilton his winter move to Ferrari could be seen as the final chapter in his glittering Formula 1 career that has made him one of the greatest drivers of all time.
But on the seven-time F1 champion's birthday, there is no better time to use the old cliché that life begins at 40 as he targets finally winning that elusive eighth drivers' championship that would take him beyond Michael Schumacher's record.
Six titles came at Mercedes between 2014 and 2020, as well as the sole title he memorably won with McLaren in 2008 in just his second season. But where will his highest F1 finish be with Ferrari? Have your say at the bottom of the page with our GPFans poll.
Who is the oldest ever F1 champion?
The Woking whizz-kid days though are now considered ancient history, which only puts his Ferrari challenge into an even greater demand as he seeks to become the sport's oldest champion since Damon Hill famously clinched his only crown for Williams at the age of 36 nearly three decades ago.
Hamilton's mission is to win a world championship in his 40s, something that has not been done since Jack Brabham back in 1966, and has also only been done once since the great Juan Manuel Fangio became the oldest ever world champion with Maserati at the age of 46 in 1957.
You also have to consider the 1950s as an age when drivers racing in their 40s was a regular occurrence. Fangio's five titles all came in his 40s and were against similar aged stars of the era such as Nino Farina, who also was F1's first world champion at 43, before younger champions such as Alberto Ascari, Mike Hawthorn and Brabham mopped up the rest of the decade.
Can Hamilton win the F1 title at Ferrari?
One big question over Hamilton's chances to win a title rest on his age and how good he can still be at 40 in a modern day context, and not from a time where trackside haystacks were the pinnacle of motorsport safety.
Luckily we have reference points. Reasons to be fearful consist of Schumacher's Mercedes career in his 40s - three miserable years of being beaten by Nico Rosberg before he was replaced by Hamilton in 2013.
Then there is the competition. Four-time world champion Max Verstappen is entering his peak years at Red Bull, while Hamilton's Ferrari team-mate Charles Leclerc has realistic title ambitions of his own. That's not forgetting the other British stars such as Lando Norris and George Russell, the latter having already beaten Hamilton at Mercedes in two of their three seasons together - including in 2024.
There is also the crucial factor of the machinery. The good news for Hamilton is Ferrari enter 2025 having only been pipped to the constructors' championship at the Abu Dhabi Grand Prix by McLaren at the final race - giving them a good platform to attack the new season. Red Bull and Mercedes also have title ambitions so it could all come down to the development race. Either way, Ferrari are major players and can provide Hamilton with the machinery he needs.
So the verdict? The competition is tough in terms of machinery and arguably more so in terms of drivers, but this is Lewis Hamilton and as far as racing in his 40s at pinnacle of F1 goes - age is just a number.