Matt Frei of Channel 4 News was interviewing Nancy Pelosi with his usual artistry and charm. You need plenty of both when tackling the Democratic titan and first woman speaker of the US House of Representatives.

Mention was made of a conversation between Pelosi and vice-president Kamala Harris, who next week seals the deal to be the Democratic nominee at the party’s convention in Chicago.

“Did she say thank you?” asked Frei of Harris.

Pelosi smiled as she once again brushed away the notion that she succeeded in getting Joe Biden to quit when everyone else had failed, thus paving the way for Harris.

“I have loved him for decades,” said Pelosi of the incumbent.

Biden and Pelosi have been pals for more than 50 years. Now their famed friendship has been replaced by an epic falling out over his retirement.

Biden’s long exit, playing out in public view, often cruelly, is a prime example of how not to retire well. Ask Ken Bruce. Like Pelosi, the Scottish broadcaster has been doing the rounds with a book to flog (him: PopMaster; her: The Art of Power).

Asked if he planned to retire, Bruce, 73, joked: “Not willingly. I don’t want to get to a Joe Biden stage. If I feel I’m not doing a job to my own satisfaction then I probably will retire. At the moment I feel quite happy, but I’m aware of not going on too long. If I start to feel that people have had enough of me, then I’ll go.”

With four million listeners to his show on Greatest Hits Radio, Bruce is a long way from that point. As is Tom Cruise, 62, who abseiled into the Olympics closing ceremony last Sunday, collected the flag, and took off on a motorcycle. Good luck telling Cruise to take things easier.

Ditto George Clooney, at 63 a year older than Cruise, who graces the cover of September’s GQ magazine with Brad Pitt, 61 in December. How did that happen? How did we all get to be so old?

Ageing is not what it used to be. Presidents, radio presenters and movie stars, like the rest of us if we are fortunate, are living and working longer, and expect to remain in good health while doing so.

The changing face of getting older can be seen in the way people dress. Look around. Compare what you see with one of the “Remember when …” photos on The Herald’s letter pages. The young women of the past, with their sensible skirts and tight perms, look like old people, while the fiftysomethings of today, all smart casual wear and highlighted hair, could be twentysomethings.

As ageing has changed, so have our expectations about retirement. The dream for many might be stopping the 9 to 5 at 55, but only public sector workers and the wealthy can hope to do so. Most of us will have to hang on for another decade-plus, longer in the future, to claim the state pension. Even then, some will choose to carry on working because they need to financially, or they enjoy it.

Meanwhile, younger workers are trying to get in the door but are finding the way blocked by baby boomers. Boomers and Gen X took the houses, snaffled the free education, and now they are hanging around the workplace beyond their best before date. But when exactly is that? Who gets to decide when a person is no longer up to the job? It is one of the abiding questions of the age, or the Biden question if you’re partial to a pun.

While there is no evidence that tolerance for puns grows or lessens as one ages, there is plenty of research that shows staying as well as you can, for as long as you can, is good for mind and body. Having a purpose is what matters.

In one recent study, the results of which were published in the Journal of Neurology, Neurosurgery, and Psychiatry, researchers tracked a group of people with an average age of 79 for 14 years. Those who did not feel they had a purpose were more at risk of developing mild cognitive impairment and that, in turn, increased their risk of dementia.

In short, use it or lose it. The advice does not apply in all cases. Some conditions have a progressive impact on your mental and physical health and there is little or nothing you can do about it. But in general, actively investing in your well-being pays off.

If we accept that is so, doesn’t it follow that forcing people to retire could do them harm? To come back to the Biden question, if he had been allowed to carry on, might work itself have powered the president through another term?

At the time of his disastrous television debate with Donald Trump, Biden had been travelling nationally and internationally while doing two jobs - president and candidate. Anyone could have a bad night after that, as indeed Biden argued was the case.

Age matters in some jobs more than others. Even then it is not that simple. Given the choice between an older surgeon and a younger one, wouldn’t you want the one who had more positive outcomes to his name?

Whatever their reasons, Americans decided an 81-year-old Biden was not for them. Poll after poll said it. He disputed the numbers, believing only he could beat Trump. In the end, it came down to sheer self-interest. His own party thought he would cost them seats and the presidency so he had to go.

Trump, one of Biden’s most relentless critics, now finds his own cognitive abilities under discussion. During his sit-down this week with Elon Musk, Trump regularly wandered off-topic and sounded tired, slurring his words at times.

According to Trump, Biden had been the victim of a “coup”.

“He didn’t want to leave and they said, ‘We can do it the nice way or we can do it the hard way’.”

Could it be that Trump, 78, now feels vulnerable because of his age? Or is Biden a standalone case?

It should be noted that a candidate is standing for re-election in November who is older than Biden. At 84 to his 81, she has no intention of giving way to younger blood. Isn’t that right, Nancy?