They've been a fixture on the Formula 1 grid in this new Millennium.
But after almost two full decades in one of the most demanding arenas around, Jenson Button and Felipe Massa are leaving the scene.
For Button, it seems the prospect of getting behind the wheel of an F1 car again does not drive him in the way it has done for so long, as he said quite plainly in the build-up to the season-ending Abu Dhabi Grand Prix.
"I go into this weekend thinking it is going to be my last race. I think that's the best way to be. At this moment in time, I don't want to be racing in F1 past this race," he said.
The British driver will go down as a world champion, having achieved that feat with Honda in 2009, while Massa came so close to becoming the first champion from Brazil since the late, great Ayrton Senna when he was pipped by just one point by Lewis Hamilton in 2008.
Those are the margins that can decide a driver's place in the pantheon.
He has taken his retirement with good grace, choosing to remember the highlights and the people who have helped him in a very classy manner on his Facebook page:
Massa started his F1 career two years after Button's debut in 2000. But both were part of the wave of drivers who started out during Michael Schumacher's era of dominance with Ferrari.
Some of the stars of that era will still grace the grid like Fernando Alonso and Kimi Raikkonen, while Lewis Hamilton, Sebastian Vettel and Nico Rosberg emerged that little bit later on but mixed it with the Buttons and Alonsos in a highly talented era of drivers.
Unfortunately for a driver as talented as Alonso, he never added any more world titles to the two he won back-to-back in 2005 and 2006 - a period when both Button and Massa were really beginning to come into their own.
However, by the start of the 2006 season, neither driver had won a Grand Prix.
But that was about to change within one August that year.
Button had been in Formula 1 for six years at that point and had shown occasional glimpses of his class.
He had made a decent start to the '06 season before a tough middle period of the campaign.
And his luck didn't look like changing when the paddock came to graze at that year's Hungarian Grand Prix.
An engine change meant he would have to serve a 10-place grid penalty at the start of the race and having qualified 4th, it meant he would start 14th on the Sunday.
But in a wet-starting race that would see championship leaders Alonso and Schumacher endure forgettable weekends, Button did not pit when the safety car came out and that pushed him up the order. And it provided the platform for his maiden career victory after being in a position to capitalise when Alonso exited.
Further back the field, Massa had finished 7th just ahead of Ferrari team leader Schumacher.
But the Brazilian's time would come sooner than he may have anticipated.
After a three-week break, the season reconvened in Turkey.
Unlike Button's weekend in Hungary, Massa would have a near-perfect round in Istanbul.
It started by sticking his car on pole in an all-Ferrari front-row with Schumacher.
He was able to hold on to that lead during the 58-lap Grand Prix to finish ahead of Alonso and Schumacher and ensure that there would be back-to-back debut winners in Formula 1 for the first time since 2003.
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