When Devin Tomb was 24, she began a new role as an editor at a teen magazine. “I knew by my second day that I’d made the wrong decision,” she said. “Behind closed doors, the editor-in-chief didn’t match the warm, friendly persona she displayed in public. It got so bad that our executive editor tried to console me one day by saying this EIC was ‛just hazing me’.”

I had a similar experience at 23, when I took a job that promised international travel — but in reality, mostly involved trips to Ohio. And it turns out this phenomenon is more common than many people realise.

According to a new survey of more than 2,500 respondents from career site The Muse, which I founded, 72 per cent of American workers said they, too, have experienced starting a new job and realising — to their surprise or regret — that the position or company was very different from what they were led to believe. Thirty per cent said both the position and the company were very different. I call this unpleasant surprise “shift shock” to distinguish it from ordinary new-job jitters. It’s normal to feel nervous starting a new job, but it can be a big problem to be hired into a role with one set of responsibilities and then be expected to perform another, or to join a company culture that turns out to be cliquey when you were sold on the idea of camaraderie.

Over the past two years, as job candidates and employers have assessed each other over Zoom, I suspect a lot of people have ended up with that “did I just make a huge mistake” feeling. And while Devin, who is now director of Editorial and Brand at The Muse, waited a year to leave her not-as-advertised position at the teen magazine — largely owing to an old-fashioned, unspoken rule that that’s how long you “should” give a new job — 41 per cent of our survey respondents said they would give a new job only two to six months before quitting. Eighty per cent agreed that it is acceptable to leave a new job before six months if it doesn’t live up to your expectations.

This is a generational shift, driven by Gen Z and millennial candidates who are more likely to believe the employer-employee relationship should be a two-way street. For many, the pandemic has only emphasised that life is short, making people less likely to stick around in unfulfilling jobs. While that may sound flighty to some older workers, younger employees are probably right to leave. When they do stay, employees who experience shift shock are less likely to be engaged or to become high performers, per the Society of Human Resource Management. That can limit career growth.

On the other hand, quitting can be expensive — for both the company and the employee. An article in Harvard Business Review estimated that employers spend an average of $4,129 per hire in the US. For new hires, losing health benefits alone can be costly, as the average cost of health insurance in the US is $541 per month. An employee who quits might also have to dip into savings, as it usually takes at least two months to go through a new job hunt and interview process.

Before deciding to quit, employees who find themselves in a surprisingly bad situation should talk with their managers. Bryn Panee Burkhart, a coach and career management expert, suggests they keep a work diary for two to four weeks, allowing them to discuss patterns with their hiring manager. “Tee up the conversation in a positive manner so it does not sound like complaining,” she says. “Take emotion out of it and come with logic and facts.” She recommends a question-statement framework to keep it congenial. Example: “I’m finding it a challenge to stick to the working hours that were agreed upon when I accepted the offer. Some important weekly meetings are scheduled outside of those hours. Can we work together to address this?”

At the same time, begin the search for a new job. (If you truly liked your old one and regret leaving, consider asking your former boss about returning to the company — many companies are thrilled to welcome back former employees.) Saving as much money as possible will make it easier to move on if a few months go by and nothing has improved. When it’s time to quit, Eloise Eonnet, a coach and expert in communication and leadership skills, says to “make it about yourself” when you tell your manager you’re leaving.

“Let them know that you were really excited about joining the team, but that you now realise that you will not be successful in the position. Keep your reasoning professional and high-level: ‛I can contribute meaningfully when I have more responsibility and autonomy in decision making. I know this about myself and need to find a role that better aligns with how I thrive.’” If you feel like the relationship warrants it and feedback would be appreciated, this can also be an appropriate time to share some of the gaps between the expectations that were set during the interview process and the reality of the position.

Given how common shift shock is, it may not always be preventable. But talking with past and present employees and asking questions designed to elicit candour — “What’s your favourite and least favourite thing about working here?” — reduce the odds of it happening again. Your sense of fulfilment at work depends on it.

• Kathryn Minshew is chief executive and co-founder of job search and career advice site The Muse, as well as coauthor of The New Rules of Work: The Modern Playbook to Navigating Your Career