Few elected officials seem more eager than Mayor Bill de Blasio to put, as he phrased it, this “God-forsaken” year behind him. But 2020 was not without its lessons for this mayor and for those seeking to succeed him.

On Wednesday, Mr. de Blasio said this year had taught him the importance of self-care, and he recommended that whoever succeeds him bear that lesson in mind.

“One thing I’ll tell you that I’ve learned — this is something Chirlane used to lecture me on all the time — that sleep really matters,” said the mayor, referring to his wife, Chirlane McCray. “And I’ve not been someone who has traditionally gotten enough sleep.”

No one disputes the value of sleep. Yet it seemed bizarre for the mayor — whose sometimes somnolent approach to schedule-keeping prompted The New York Post to give him an alarm clock in 2014 — to focus on his sleeping habits.

Sure enough, his comments provoked ridicule on social media, another Post front-page headline — “Bedtime for Blasio”— and an opportunity for several mayoral hopefuls to offer their own lessons that they learned this year.

Here’s what you need to know about the week that was in the mayor’s race.

The path to City Hall still goes through Harlem

Before actually running for mayor of New York City, many candidates follow an informal task list: Quietly consult with New York political hands; register a campaign committee but insist it is merely exploratory in nature; and then, after a dutiful amount of time has passed, declare.

And somewhere in the middle of all that, meet with the Rev. Al Sharpton.

Representative Max Rose of Staten Island is most of the way through that process. He met with Mr. Sharpton in November and filed for his campaign committee in early December but has yet to formally announce he’s running.

He’s now in lock step with Andrew Yang.

Mr. Yang met with Mr. Sharpton on Tuesday, and on Wednesday, he formally opened a mayoral campaign committee with the New York City Campaign Finance Board. Per the script, someone close to his formative campaign insisted the move was merely procedural — that Mr. Yang registered so that if and when he decides to run, no bureaucratic hurdles will stand in his way.

In an interview, Mr. Sharpton said Mr. Yang was better prepared than he had expected him to be. Mr. Yang, who ran for president on the promise of creating universal basic income, talked about alleviating poverty, improving broadband access, food deserts and bringing “the fizzle” back to New York City, Mr. Sharpton said.

The meeting came about because Mr. Yang asked for it. That’s no surprise, according to the reverend.

Mr. Sharpton runs a prominent civil rights organization, hosts his own radio and television shows and holds weekly rallies simulcast on the radio. He says more than 60,000 people tune in.

“Some of the right-wing media says, ‘Oh, they’re kissing Sharpton’s ring,’” Mr. Sharpton said. “No, they’re using my platform to talk to prime voters.”

Another one joins the scrum

Art Chang, a former JPMorgan Chase managing director, is not the first mayoral candidate to position himself as an outsider — someone who is not beholden to special interests or burdened by decades of political baggage.

But no other outsider shares his back story: a Korean-American resident of Prospect Heights, Brooklyn, with a degree from Yale in women’s studies and a childhood spent with an abusive father.

On Dec. 21, Mr. Chang, 57, announced he was running for mayor, and on Thursday he released his first campaign video.

He says his heart is “on the far left,” but it’s also important to be able to get things done.

Comparing himself to his competitors, he said, “I don’t think I’m like any of them, and I will put myself in a lane which is very, very different from any of them, because of what I’ve done and what I’ve been through in my life.”

Mr. Chang was born in Atlanta, grew up in a white school district in Akron, Ohio, and lived with an abusive father and a strong mother, he said. He has worked in and around city and state government since the 1990s, including at the corporation counsel’s office and at the agency now known as Empire State Development. He has also worked in venture capital and has served on the boards of the Brooklyn Public Library, Safe Horizon and the Campaign Finance Board.

Should he become mayor, he would institute universal day care for all children from the age of 1 to serve “a city of people who primarily live on the edge.”

“These communities need leadership now more than ever,” Mr. Chang said.

They’re just like us

As it turns out, being a mayoral candidate in the year 2020 is not all that different from being any other sort of New Yorker in the year 2020: You spend a lot of time at home.

Forced off the hustings by the threat of contagion, the mayoral candidates have been severely constrained in their ability to glad-hand parishioners at Brooklyn churches or kibitz with nursing home residents.

Asked to reflect on the lessons they’ve learned about themselves, they will say, like so many of us, that 2020 has reminded them of what they truly value — time with family, small acts of kindness, the release that comes from a walk in the park.

“The pandemic has brought us back to the family dinner table, reminding us that we like sitting together,” Maya Wiley, the mayor’s former counsel, said. “But I’ve learned that listening to each other, hearing about our days and what’s on our minds is also a matter of emotional survival.”

Joycelyn Taylor, who owns a general contracting firm, said this upside-down world has reminded her of the importance of flexibility. “The expression, ‘We make plans and God laughs,’ comes to mind,” she said.

As the father of two young children, Scott M. Stringer, the city comptroller, faced another challenge.

“I also had to learn how to do third-grade math,” he said. “It’s a humbling experience, especially when you’re essentially the chief accountant of the City of New York. In my defense, they changed math.”

As for sleep?

“I already knew the value of sleep,” said Kathryn Garcia, the mayor’s former sanitation commissioner who is now running for mayor herself. “I’ve done a few emergencies in my time.”

No one is immune

The virus has profoundly changed the mayoral race, dominating the issues and affecting the way candidates raise money and gather attention. It has also hit some candidates more directly.

Shaun Donovan, a former Obama administration housing secretary now running for mayor, caught a mild case of the virus earlier this year. Mr. Stringer’s mother died of Covid-19, and now Ms. Wiley is in quarantine following a possible exposure.

“I’ve been in contact with someone who has tested positive for Covid,” she wrote on Twitter last Tuesday. “So quarantining for 14 days and awaiting my Covid-19 test results.”

The well-wishes poured in, including from Mr. Adams, the Brooklyn borough president, who said he hoped to see her back on the campaign trail soon.

Ms. Wiley is the first major candidate to be sidelined from a race that — like much of life these days — is largely being conducted from the sidelines, anyway.

After Mr. Stringer’s mother died, he mourned with those who loved her, remotely.

“I didn’t know you could have a shiva over text,” he said. “But that’s 2020 for you — we all learned that you don’t need to be together to feel close.”