If, for Ryan Dichter, Week 1 of his coronavirus isolation was a time for dandling his infant daughter, Teddy, slouching around in sweatpants and waiting for the happy-hour start gun, it became clear to him, as the terms or our collective confinement wore on, that the time had come to shower up and tug on some hard pants.

“At first every night was Friday night,” said Mr. Dichter, 36, a real estate agent who sells luxury residential properties in New York. “I was watching too much TV and having a few too many cocktails because it was unclear where this was going. Fast forward, and it’s time to get properly dressed. School night’s still school night.”

Since the first coronavirus cases were reported in this country, the terrain of the average workday shifted with seismic force and suddenness. Workplaces were abruptly shut down, and, for those that still had jobs, the office became that chair in a corner by the closet. Business was transacted largely on Zoom. And, unless the phone slipped, no one knew that you were multitasking while half-naked below the waist.

Rituals once thought fundamental to organizing a presentable version of oneself for the public were now called into question. Who says a guy has to shave and shower in the morning? How come you need shoes when you can’t leave the house? Why not slap on a ball cap if you have a bad case of bed head?

Yet, as it becomes evident that the state of house arrest is likely to be prolonged, old conventions begin to reassert themselves.

Increasingly, the need arises to sharpen one’s presentation onscreen, as a means of standing out amid the “Hollywood Squares” grid of a monitor or merely to establish for your colleagues that, when the Google calendar meeting alert popped up on your smartphone, you were not still rubbing sleep from your eyes.

“I was joking around with a friend that we’ve all become cam boys and cam girls now that we’re just individual boxes on a screen,” said Timo Weiland, 36, the creative director of the men’s wear label that bears his name.

Locked down at home in Brooklyn for the last three weeks, Mr. Weiland has found an urgent need to reinstitute daily grooming and dressing routines that he let lapse when it appeared that few of his business encounters were going to occur in a physical space.

“It’s about preserving a sense of professionalism in a formless environment, where the sense of urgency is gone,” he said. “I have seven to 10 Zoom meetings a day, and I feel far less prepared if I’m wearing a hoodie-and-pajamas look.”

It was Adolf Loos, the Austrian architect, theorist and dandy who once posited, in his short-lived journal, Das Andere, that a person is properly dressed not when he stands out but when he is wearing the correct apparel for the moment at hand. By that standard we should all be wearing battle gear.

Yet Mr. Weiland gets by with one of his label’s relaxed fit cotton twill chambray blazers worn with James Perse T-shirts and a pair of forest green velvet Vans slippers that “go with every shade of Levi’s I own.”

When working from home, Mr. Weiland forgoes obligatory fashion black for bright colors. “I like the way they pop,” he said. “And it stimulates the way I communicate online and on video, even if I’m just taking one step forward to the countertop.”

For Jordan Fudge, 27, a venture capitalist in Los Angeles, the world of work has been Zoom-centric for long enough that being at home has not significantly altered how he dresses for the job. That is, he continues to wear the comfortable though casual athleisure basics that are all but obligatory in his field. He does, however, “smarten things up a little bit,” he said.

“You want to make sure you are not on camera stained with Cheetos dust.”

You also want to make certain you don’t undercut your delivery, as Seth Meyers did on a recent edition of “Late Night,” lighting into President Trump for greed and assorted villainies from his home office, though dressed — in a patch-pocket wool shirt over a slack-collared T-shirt — as if he’d just come from cleaning out the garage.

Conjuring functional new norms of dress for a nation thrust forcibly into modes of work still unfamiliar to many will take time, Mr. Fudge said. “We’re getting there as a culture,” he said, pointing out that “The Daily Show” host, Trevor Noah, for one, has adapted nimbly to the new normal, shedding the sharply tailored suits he typically favors on air for denim button-downs and high-end hoodies.

“We need to appear to be in control, even if everything is out of our control,” Mr. Fudge said.

Other factors are key to dressing for work, according to Konrad Olsson, 38, the founder and editor of Scandinavian Man. Speaking by phone from Sweden, Mr. Olsson pointed out a truth perhaps lost on those for whom wearing a three-piece suit seems as alien as climbing into a coat of arms.

The traditional suit, he said, was a form of protective gear, a means for demarcating boundaries between public and private, work and leisure, the exigencies of the corporate world and the intimate needs of one’s family life.

“Gay Talese has always been a true inspiration for me,” Mr. Olsson said, referring to the New Jersey-born journalist who, descended from a long line of tailors, holds fast to a belief that dressing up each day for work is a profound and civilizing, almost devotional act.

“He always talks about dressing up for the story,” Mr. Olsson said. And it is true that, even at 88, Mr. Talese continues to knot his tie and slip on a jacket each morning before descending the stairs to the home office in the Upper East Side townhouse he has lived in for decades.

“I don’t have my office, I don’t have my desk, I don’t have my co-workers and the other attributes of a job around me,” Mr. Olsson said. “I’m sitting in my 9-year-old daughter’s room working on all these Zoom calls.” Putting on a blazer, he said, not only lifted his mood but also helped him restore the “structure and contour” of days that had begun to puddle around his slippers.

Switching out jeans and “yesterday’s T-shirt” for a velveteen suit and tie, blazers and khakis, a double-breasted suit and sandals, he began posting self-portraits to his Instagram account @konradolsson with the legend “No Casual Fridays in a Crisis.”

“It sounds pretentious, but it’s important that I dress this way,” Mr. Olsson said. “It’s showing the world that I put value in our time and what we do together.”

Brian Tran, 28, a founder of Serif, a co-working start-up, quit New York for Colorado just before the shutdown. For him, organizing a daily wardrobe is his way to “create structure and a routine that are incredibly important to me.”

Noah Jay, 28, a commercial real estate broker in Manhattan, knows it would be “ridiculous to wear a suit in your house,” but there remains an impetus to reassure clients that, though leases everywhere are now being renegotiated, it still pays to think long-term.

“I represent a lot of fashion clients, and obviously I’m going to dress differently for a big Israeli investor than when I’m representing someone with a new shoe line who wants to do a pop-up in Brooklyn,” Mr. Jay said. “Either way, I don’t want someone seeing me onscreen and saying: ‘Oh, wait. What are you doing.’”

Even for James Cusati-Moyer, 30, an actor, who has never held a desk job and who last observed a dress code as a waiter in college, there is something to be said for dressing up to greet the day as a means of boosting self-esteem.

The streaming series he began filming in Canada after his Broadway run in “Slave Play” ended is on pause, and his tape auditions have slowed to a trickle. Still, as Mr. Cusati-Moyer said, “There are only so many hours a day I can remain in the clothes I slept in the night before.”

So, even on days when the shape of his life is defined by FaceTime encounters and bounded by the four walls of his apartment, he dresses in a vintage T-shirt and Uniqlo trousers, which is the normally peripatetic actor’s travel uniform.

As a video game producer who also teaches at the Tisch Center for the Arts, Jeff Petriello, 33, makes an ideal poster boy for those whose every day is Casual Friday. Yet since the quarantine began — and as successive Zoom meetings stretched out for as many as eight hours — Mr. Petriello has found himself focused on his hourlong grooming ritual and morning forays into his closet where he marks each new day on lockdown by “turning a look.”

“People express themselves in different ways, and fashion is a way I learned to,” Mr. Petriello said.

“That routine is something I’m trying to stick to,” he said. “It makes the day feel more real if I wake up and think, ‘That’s what I’m wearing!’ Even if nobody’s seeing me.”