Preplanned time off in regards to job searching

Hello,
I've always been told that you should not mention any preplanned time off unless you receive a job offer or if you are asked about it in an interview.
But, now that it has been an employer's market for so long, have any of you ever mentioned any time off during an initial interview?
Just curious...on the one hand, I feel it is a good idea not to take time off at all during a job search, but then again, I can't let the job search consume my entire life, as in there is a life outside of work and job searching as well.
If so, have any of you had potential employers show any flexibility?
I know if would'nt be paid time off, of course, but just wondering if anyone has had any feedback in regards to mentioning it during an initial interview and asking about it own their own initiative?
Thanks!
DD