A daily shower is an ingrained habit for most people. Many would no sooner disclose they had not showered in days than admit infidelity. But Jenefer Palmer, 55, cheerfully admits she doesn't shower or shampoo daily and doesn't use deodorant. Ever.

No, the Californian does not work from home in pyjamas. In fact, Palmer, the chief executive of Osea, an organic skincare line, often travels to meet business contacts at the five-star luxury hotels where her line is sold. They might be surprised to read that Palmer, a petite brunette, showers "no more than three times a week," she says, and less if she hasn't been "working out vigorously".

She contends that a soapy washcloth "under her arms, between her legs and under her feet" is all she needs to get "really clean". On the go, underarm odour is wiped away with a sliced lemon. Defying a culture of clean that has prevailed at least since the 1940s, a contingent of renegades deliberately forgoes daily bathing and other gold standards of personal hygiene, like frequent shampooing and deodorant use.

To the converted, there are many reasons to cleanse less and smell more like yourself. "We don't need to wash the way we did when we were farmers," says Katherine Ashenburg, 65, the author of The Dirt on Clean: An Unsanitized History. Since the advent of cars and labour-saving machines, she continues, "we have never needed to wash less, and we have never done it more".

"I'm going to sound like dirty Katherine in this article," she says, "but it doesn't matter. I'm still invited to dinner parties!"

Retention of the skin's natural oils and water conservation are two reasons Palmer and others cite for skipping a daily shower. Some have concluded that deodorant is unnecessary after forgetting it once with no social repercussions, or are concerned about antiperspirants containing aluminium, even though both the National Cancer Institute and the Alzheimer's Association don't share those concerns. Shampooing as little as possible can help retain moisture in dry locks and enhance curl shape, argue adherents of the practice; for some men, it's about looking fashionably unkempt.

Resist the urge to recoil at all this. They may be on to something. Of late, researchers have discovered that just as the gut contains good bacteria that help it run more efficiently, so does our skin brim with beneficial germs that we might not want to wash down the drain. "Good bacteria are educating your own skin cells to make your own antibiotics," says Dr Richard Gallo, chief of the dermatology division at the University of California, San Diego, and "they produce their own antibiotics that kill off bad bacteria".

Some people have long complained that showering too much makes their skin drier or more prone to flare-ups of, say, eczema, and Gallo says that scientists are just beginning to understand why. "It's not just removing the lipids and oils on your skin that's drying it out," he says. It could be "removing some of the good bacteria that help maintain a healthy balance of skin".

But Elaine Larson, a professor at the Columbia University School of Nursing who has a Ph.D in epidemiology, cautions that subway riders, gym-goers and others who come into contact with many strangers should consider soaping up. "If it's cold and flu season, you want to get rid of the stuff that isn't your own normal germs," she says.

Whatever the motivation, personal cleanliness has long been big business. Widespread advertisements address (and arguably generate) anxiety about body odour. They seem to work: Adults younger than 24 use deodorant and antiperspirant more than nine times a week , but even for older age groups, use never falls below an average of once a day, according to Mintel, a market research firm. Ninety-three per cent of American adults shampoo almost daily, the firm says. Reliable statistics for how often Americans shower are hard to come by, says Regina Corso, a senior vice-president of the Harris Poll. "People are going to be hesitant to say they're not showering every day," she says.

But Todd Felix, a clean-cut-looking actor and online producer at Sony who lives in Los Angeles, is happy to report that he finds deodorant unnecessary and antiperspirants absurd. (To his mind, the latter is akin to covering your pores in plastic wrap.)

To keep his body odour in check, he takes a daily shower with an unscented body wash, usually after the gym. But Felix, who is in his early 30s, is cautious about disclosing that he doesn't wear underarm protection to people he dates. "When you tell a person you don't wear deodorant, you come across as, `Oh, how European, how natural, how funky,'" he says.

The few times Felix has mentioned on a date that he goes without deodorant, he says, things quickly turned, well, sour. "It's weird, but I don't smell," Felix will announce. Then, he says, "the comment is always, `You think you don't smell.'"

America's custom of rigorous cleanliness was in full swing by the second world war, says Ashenburg, the author of The Dirt on Clean, and intensified with post-war marketing. But things are changing. An article in Parenting magazine's November issue suggests that stressed mothers need not shower daily, stating reassuringly: "The air is drier in the winter, which means you need your skin's natural lubricants."

Meanwhile, sales of dry shampoo - a spray used to prolong the time between wet washes - "more than doubled" from 2007 to 2009, according to the NPD Group, a market research firm.

Alice Feiring, a wine writer in Manhattan, jokes that autumn is her "season of non-bathing" (she actually does it four times weekly). "Didn't I bring you up differently?"she says her mother asks. "What will people think?" But Feiring, 52, is resolute. "I don't like to over-dry my skin," she says. "It's a myth that people need a deep cleaning every day."

The New York Times