Because they are so good that the company was always willing to give them more to keep them on board. While they didn't care about positions name.

Why is it extremely fishy?

A smart person would get bored of maintaining a Spring app for a decade.

@LauriElias Or they're happy with what they're doing and have plenty of diversity in their role.

Or possibly the next level up is too many meetings with no real outcome compared to achieving something useful at the level they are...

@LauriElias: “A smart person would get bored of maintaining a Spring app for a decade” — there are so many completely baseless prejudices wrapped up in that little statement.

FWIW I work in a very small company <10 people and it has been this small for years before I joined. There is no where to move up within the company and my role is extremely diverse because of the nature of our work and the few staff we have. So it isn't always a case of someone not being able to move up in the company, maybe they just can't.

I think the correct question you need to ask yourself and him is why you want to leave your job after working 15 years

You should actually ask him. This makes a perfectly valid and potentially very interesting question for an interview. If he seems embarassed and comes up with excuses, then it's a red flag. If he confidently gives some of the valid explanations given in the below answers, then you have no reason to exclude this candidate.

I find it amazing that some people find an individual who is not interested in climbing the corporate ladder and achieving world domination to be suspicious.

I would be more than happy to be checked by a doctor with 15+ years of experience on his field. Or to watch a lecture from a teacher with 15+ years of experience on his subject. Or to eat the food from a chef with 15+ years of experience on the kitchen. Why software development would be different?

Heard of the Peter Principle? Apparently there are people who somehow manage to avoid it.

So longevity and commitment are now seen as "fishy" and suspect? What a world.

Wouldn't it be more fishy if this person changed their job every year and always did something completely different than before? You prefer those who change their mind every day? Then you better shouldn't interview ;-)

@gburton I find it even more fascinating that we are now able to find something extremely fishy in each and every curriculum. No matter what you do. It's always wrong...

@gburton I don't find it amazing, I find it depressing that there are people with this viewpoint around, and in a position where they are able to influence hiring decisions. Whatever happened to just going to work and doing your job to the absolute best of your ability?

See the related question, in which I ask the opposite question (in what I hope is a neutral way): workplace.stackexchange.com/questions/130367/…

I worked at my previous job for 15 years. I've worked at my current job for 13 years. Why is this a problem?

It could be that this candidate lucked out on negotiation on their last post and was hired at 2x the average pay for the skills. It's taken this long for inflation to catch up for them to see an incentive to switch jobs.

@BobJarvis Clearly you lack the ambition required to be a Good Citizen. (do I really need the sarcasm tag?)

Why do you think this person has done the same thing endlessly? Why isn't it possible that they worked on a succession of different projects? I was at a company for about that long and I worked on a pretty wide variety of projects. I certainly wasn't doing maintenance on one program for 15 years!

Maybe he just knows what he loves and wants to do. :-)

You say he's a senior software developer. Was there a higher engineering position available with his employer, the one where he'd still get to write software? If not, and if his only other option was management, perhaps he actually enjoys programming, and didn't care to do a completely different job, one focused on people and organizational issues.

Imagine the situation if it would be a red flag. "Hey boss, I'm super happy here, love the benefits, love the team. However, I've been working here for 3 years already and I don't want to be a manager, soooo... I'll quit now and work somewhere else."

There seems to be an assumption that AnonOP is concerned this person hasn't been promoted, but is it possible that AnonOP is actually concerned that the applicant hasn't switched companies? While that may sound like an odd concern, it's reasonable in this system created and perpetuated by corporate America itself; When it's normal for annual raises to fall in the 3% - 4% range, while moving to a new company for the same job will net a 10% - 20% increase in pay, I think staying in the same place too long can unfortunately imply a bit of 'unhirability'.

The length of time that employees tend to stay at a single company or role is highly dependent on the industry, as well as specific company culture and the type of position. I have had recruiters reference this variability directly with phrases like, "Once people join [company], they tend to retire there" or "Once you've worked at [company] for a couple years, you can get a job anywhere." Can you garner any sense of what is a 'typical' tenure in his previous company or industry?

How long have you been a senior software engineer? How many other senior software engineers do you know? How long have they been at their current job? How much time should pass before you have to search for this person's replacement? How long before you move up the chain?

Was it the same position for 15 years or were there promotions involved? For example, I've been at the same company for 4.5 years but have had a couple of promotions and am also a team lead, but depending on the context I might just say I've been a developer the whole time, because it's accurate, I still primarily do development and always have.

You should also be explicit about your own goals and standards. Apparently, in 15 years you want to be something other than a Senior Software Developer - or you would not suspect that there's something "fishy" about your interviewer. What, exactly, are you aiming for? Senior management? CEO? Have you considered that those who are competent at software development are often not suited for management? Why do you think that software development is a good choice for the bottom of your desired career track? Or do you expect to leave the company in a few years for a big raise?

I'm still mystified as to why on earth dedication and loyalty would be a red flag to anyone.