WASHINGTON (AFP) - They tidy the baggage carts in airports, sell clothes or work as cashiers in supermarkets at an age when their peers have long retired.

Working after 75 is becoming less and less unusual in the United States.

Ms Sandy Thorpe, 76, is part of this growing cohort of Americans who continue to toil in their later years. By necessity, but by choice too.

"One of the main reasons I continue working is I have a very good medical insurance," she said.

Healthcare is a common concern in a country where medical costs can be in the tens of thousands of dollars and quickly eat through a lifetime of savings.

Ms Thorpe started working 16 years ago. After a short time running a cleaning service, she is now correspondence coordinator for a prison fellowship, located in Virginia, near Washington.

When she divorced, she had to face facts: Her modest pension was insufficient to pay the bills or heal properly from an injury received playing soccer. An active women's soccer league in the Washington area includes divisions for players over 50 and over 60.

"I am lucky," she said. "I am in great health. I love my job. I work for a non-profit ministry, I help people who are in need."

And in addition to the health benefits, "it keeps my mind sharp", she said, adding that she doesn't even use all of her vacation days each year.

"I will stay as long they want to have me."

GOOD NEWS FOR SOME, NOT OTHERS

Ms Thorpe, a mother of five and grandmother to 12, feels all the more privileged since many other seniors are forced to accept gruelling jobs, packing parcels all day long or cleaning offices.

The phenomenon of older Americans continuing to work "is slightly more a bad news story than a good news story", said Mr Jacob Kirkegaard, an economist at the Peterson Institute for International Economics.

For people with advanced education, continuing to work until 80 or even 85 is associated with an increase in life expectancy.

With all their mental faculties, they can continue to work as teachers, lawyers or doctors, adjusting their schedule as they see fit.

And with many businesses complaining they cannot fill open positions, these older workers participate in the country's economic expansion.

But "the problem is there is another group of Americans that continue to work for purely financial reasons", Mr Kirkegaard said. "People forget that close to half of Americans have no private retirement savings."

The share of people aged 75 and over who are in the labour force jumped to 8.3 per cent in 2017 from 5.3 per cent in 2000.

At the same time, for those over 80, the rate doubled to 6 per cent, according to US Labour Department data.

Many are casualties of the 2008 financial crisis: The collapse of the financial and real estate markets occurred as a large proportion of baby boomers were approaching retirement.

Many who were counting on their mutual funds to support their old age saw their savings wiped out and their homes worthless or forfeit.

"They don't have other choice than continue to work. They simply cannot retire," Mr Kirkegaard said, noting that the US has the highest income inequality among retirees in OECD, due to the lack of a sufficient public pension system.

Mr Allan Shedlin, 77, only recently left his job at a grocery store in the suburbs of Washington, his second career.

His first was as a teacher in New York. "Nobody goes to this profession to get wealthy," he said. "And my retirement plan was not enough to retire." He was 63 when he started working for Trader Joe's.

"I must say for the first two months it was a little bit humiliating," Mr Shedlin said, admitting he was not used to doing menial tasks like cleaning up spills.

MORE RELIABLE

The early days were also exhausting, since he had to adjust to shift work, and help unload trucks carrying pallets of food.

But Trader Joe's offers some benefits like good medical coverage and discounts on store products. And later, he was shifted to a role dealing more with customers, where he excelled.

Mr Shedlin, who is divorced and has three daughters, one son and eight grandchildren, probably would have continued the job, but he received an inheritance that allowed him to devote himself fully to other projects.

"I shopped there and it is a fun place to work," he said.

Since the issues of healthcare costs or retirement savings is not likely to go away, the trend of Americans working longer will continue, says Mr Kirkegaard.

And as companies continue to struggle to find enough workers, employers will make increased use of this experienced workforce, that has the reputation of being more reliable than their younger counterparts.

Some swimming pools have reportedly hired lifeguards even into their 80s, eschewing the traditional teenage workers to fill the role.