In which case the applicant's employment history would be a lot more relevant. As in, have they been job-hopping, historically "not-lasting" at a job? or do they commit to their work and see it through. If you're offering a decent job and pay fairly, there's no reason to assume an applicant will simply "not last" only because of them being "over-qualified", whatever that means.
I’ve personally applied for jobs I’ve been overqualified for with the intent of getting in the door and moving out of that position as fast as possible. That might be good for me, and good for the hiring organization, but I totally understand the hiring manager blowing me off, because I wouldn’t be filling his need, and in a couple months he’s back to sorting through resumes and doing interviews.
No, sorry. The issue is that a job that pays fairly for the position doesn’t feel fair to someone who is settling until they get the job they really want. That kind of person really is likely to leave quickly. Whether it’s worth hiring someone who wants to leave immediately depends on how quickly the company can get new hires up to speed and how much effort they put into interviewing.
Now, a company can define overqualified incorrectly. And they can misjudge the cost of a temporary hire. But people really do apply for jobs they think are beneath them until they get an offer.
I disagree, and feel as I mentioned that they candidate's history is more relevant than their age and a non-defined over-qualification. In any case, when that's a worry, bring it up as a concern during the hiring process, work it out with the candidate. Now I cannot deny it happens, as demonstrated by @WillPostForFood in this sub-thread, but that does not mean everybody, not even most candidates think along the same lines. A lot just want an honest job that pays fairly, and as I stated originally, their history would likely be more telling in that regard.