But here’s my problem: When I first heard about the merger, I thought there would be significant overlap between the two companies’ employees, so I started a job search “just in case.” It’s going okay — I’ve gotten several interviews so far — but I’m running into an obstacle I didn’t expect, especially with younger interviewers. Every time someone notices I’ve been at one company for almost two decades (albeit with two promotions to bigger jobs and titles), he or she looks at me as if I have two heads. Is there a stigma attached to longevity now? How do I deal with this? — Loyal to a Fault

Dear Loyal: “No one should apologize for staying with a good company for ‘too many’ years,” says Patricia Siderius, managing director of executive outplacement services at global HR consulting firm BPI group. “These days, not many people have the opportunity to do it.”

Too true. In a weird reversal of the old, unwritten rules, frequent job changes have become not only more acceptable to hiring managers than they used to be, but “almost expected,” she adds. This is for three reasons. First, during the recession, necessity obliged so many people to move around that the old job-hopping stigma all but disappeared. At the same time, the information technology industry — where frequent job changes have long been the norm — has become the job market zeitgeist.

But the most interesting part of this shift is that it’s also partly based on a myth. Millennials, that huge (and hugely influential) generation born since 1980, are widely believed to switch jobs far more often than their parents did. It’s easy to see where that idea came from. The Bureau of Labor Statistics reported last year that the average 25-year-old has already held 6.3 jobs since age 18.

That sounds like a lot, and it is. But a new BLS report sheds different light on those statistics. The National Longitudinal study of Youth 1979, a survey of 9,964 men and women who were polled in 1979 and most recently (at ages 47 to 56) in 2013, shows that this group had held 5.5 jobs between the ages of 18 and 24 years. If people who were 25 in 1979 had been included in this project, these Boomers would almost certainly have matched or exceeded Millennials’ much-vaunted 6.3 jobs.

So Millennials aren’t as different from their elders, at least in this respect, as people tend to think. But, now that the oldest among them are in their mid-thirties and interviewing job candidates, how do you persuade them that 17 years at one company isn’t “too long”?

Siderius has three suggestions. First, write down everything you learned and achieved at your current company. Making sure you don’t overlook anything may take some thought. Siderius has noticed in executive coaching sessions that “people tend to underestimate their own accomplishments. You may be taking for granted parts of what you did.” If some of it was a while ago, you may even have forgotten it.

Once you have put together a detailed list, see which items on it most closely match up with the description of the position you want. Siderius helps her clients come up with “a one-page summary that looks like a chart, with specific job requirements on one side of the page and, on the other, the aspects of your experience that can add the most value. Then, hand it to the interviewer, in addition to your resume, and talk in specific terms about what you can do for this employer.”

Second, she suggests, be ready to toss some references to current industry trends into the conversation. “Having stayed in one place for a long time does not make you dreary and dusty. Being sharp and up-to-date on what’s current and new can help demonstrate that.”

And third, but perhaps most important, “be very positive and upbeat about the company you’re thinking of leaving,” Siderius says. “It’s important to emphasize that you’ve had a terrific run there, and that it has been a great place to work, with smart people and lots of resources and opportunities to learn.” Your enthusiasm, especially if it’s genuine, should go a long way toward quelling any skepticism about why you stuck around. Good luck.

Talkback: Has a job interviewer ever questioned why you stayed so long in one job, or at one company? How did you respond? Leave a comment below.