During the early part of my working life, I changed jobs a lot. Sometimes that was due to the market (internet start-ups came and went pretty quickly), and at other times it was simply me trying to find my dream job.
In those days job ads were both online and in local newspapers, and I read a lot of them, applying for many jobs where the actual position was not clear. That's not uncommon even now, because sometimes a company lists a position that currently has someone in it. Keeping the ad blind stops that person who's going to be fired from knowing, but it can make it tricky to get the right applicants.
That's not the only reason a job listing might be vague, but whatever the reason, if you apply for a job and get a call, you should go on the interview. You may be tempted not to once you learn the details of the position, but ignore that temptation.
You may find a hidden gem
When my now-13-year-old son was four, I had decided it was time to move on from my family ladder and scaffolding business that I had joined when he was born. I went on a lot of interviews, hoping to make my way back to journalism, but remote work was not much of an option at that point and there were not a lot of editorial jobs where I lived.
Because of that I applied for a number of management positions. I interviewed for, and turned down, a well-paying job running a plumbing supply store and I passed on a number of jobs that were sales oriented.
Ultimately, I was offered an interview to be general manager of a toy store. I pictured a little place in a strip mall or one of those sad discount shops in a regular mall. I came very close to passing, but decided to meet with the firm recruiting for the position.
They gave me a couple of personality tests, and told me I should see the store and meet the owner before saying no. They gave me the address and that weekend I visited a huge converted warehouse that was part toy store, part hobby shop, part train store, part museum, and part activity center. A few days later I met the owner and clicked instantly, immediately forging what would become a strong multi-year working relationship and friendship.
Obviously not every blind ad results in a really cool job, but you should still embrace the chance to interview. Even if you have no interest in taking the position, be open to surprises, and appreciate the chance to get another interview under your belt. Consider it a practice run that may help you ace the interview for a job you actually do want down the line.
In addition, sometimes going on an interview introduces you to a hiring manager who may have a job for you in the future. If you like the company, but not the job, it's OK to send a note saying "I'm pretty sure this position is not for me, but I'd be interested if anything came up in (whatever department you want)."
You never know
Turning down a job interview is passing up an opportunity. The position may surprise you, or maybe the salary will be well more than you expected. Perhaps the interviewer will become a new connection or even a friend.
It's easy to turn down a job offer, but it's not possible to know what you have missed by passing on an experience. At worst, going on an interview will be practice for next time, and it's possible it could be much more. Embrace that chance and never say no when offered an interview opportunity.