The bartender arrived early, stayed late, and offered to help other kitchen staffers. Still, he said, his boss told him to “show initiative” — then slashed his hours.

So, 20 minutes before his shift started on a recent Friday, Lucas fired off a parting group text to management: “I deserve better … so I went out and got better.”

He had already accepted a better-paying offer from a restaurant in his home city of Tacoma, Wash. He landed the new opportunity in less than a month.

“I showed ‘initiative’ by finding a new job,” said Lucas, 26, who spoke on a first-name-only basis to protect his reputation in the workplace. “I knew I deserved to be treated better.” He shared his farewell message with the Washington Post and redacted the club’s name.

Once taken for granted as a professional courtesy, the two weeks' notice standard is losing relevance in an economy where practically everyone is hiring, analysts say. More jobs are open in the United States right now than there are people looking for work.

The nation's unemployment rate has clung to a 49-year low since September, prompting many firms to raise wages and expand recruitment efforts.

Workers have less incentive to respect the old norm, said David Lewis, chief executive of OperationsInc, a national human-resources consulting firm. Over the last year, he has seen a 20 percent upswing in employees departing less than two weeks after they give notice.

“It’s absolutely being directly impacted by the unemployment level, the lack of available talent, and the number of positions companies are trying to fill,” Lewis said.

Others are skipping even text resignations. The Chicago Federal Reserve noted in a December report more employees are "ghosting" their jobs, quitting without telling anyone and becoming "impossible to contact."

Sudden exits can burn some professional bridges, especially when they can hurt business. Managers who scramble to pick up the slack at peak hours are not likely to deliver glowing reviews down the road.

Only a tiny share of workers in the United States have signed contracts that compel them to extend an advanced warning — mostly teachers and other professionals who agree to special terms, said Austin Kaplan, an employment lawyer in Texas.

Contrary to popular belief, he said, workers do not carry a permanent record of their exits, friendly or otherwise.

Employers generally will not give bad references because they know people can sue them for defamation, Kaplan said. A neutral review — verification of employment dates, title, and pay — is the more common outcome.

“Once you’ve left the company, there is no benefit to the employer for talking smack about your performance,” Kaplan said. “It’s an urban myth that you have to give two weeks' notice and that if you don’t, you’ll get in trouble.”

Still, Lewis, the human-resources consultant, cautions that bad reputations can spread. Plus, people who pack up early could be leaving money on the table.

“Companies are coming to the rapid conclusion that it will take them months to replace certain people,” he said, “so give them time to make a counteroffer.”

Some workers, however, encounter hostility as they try to quit.

Jason, 33, a real estate accountant in Manhattan, said he was sweating and shaking this month when he gave his manager two weeks' notice.

He had been job hunting for a year and the right opportunity had finally opened. Unfortunately, it came amid his office’s busy season. His boss wanted him to stay longer. (The Post agreed to use his first name only because he was still employed at the firm for another week.)

"She said, ‘I hope you know payback is a b—,’ " Jason said. " ‘New York City real estate is a really small world.’ I took it as a direct threat to my livelihood."

After talking to a labor attorney, Jason learned threatening retaliation could be grounds for a lawsuit.

Christian Cabazos, 31, a social-media manager in Austin, Texas, said she learned the hard way that courtesy is optional.

She was laid off last year from an event-planning job in Austin, effective immediately, and contested the news: Wasn’t she supposed to receive at least two more weeks on the payroll as she searched for another job?

Her parents had taught her to always give significant notice. She assumed it worked both ways.

“My boss explained that he didn’t have to,” she said. "He said, ‘We have the right to terminate whenever we want, and you have the right to leave whenever you want.’ "