Allergies aren't the only signs of aging - musical taste and experience would seem to be an indicator. I work graveyards at a mall that pipes in music 24/7 to keep kids from loitering. Muzak? No, nothing that horrible. No the music they picked is categorised as "oldies". Some of it is, lots of doo-wop - The Penguins, Frankie Lymon, Gene Chandler, Marcels. I have also heard Link Wray ("Rumble"), Dick Dale ("Pipeline" and "Miserlou"), Donovan ("Atlantis", "Hurdy-Gurdy Man"), The Hollies ("Bus Stop"), The Zombies ("Time of the Season"), The Beatles ("Nowhere Man") and many many others whose music I have heard since I was a kid and still like to this day.
Of course, many of my friends like, or at least can handle listening to this kind of music. I have visions of large groups of 30 somethings gathered and loittering under the speakers enjoying music that they really might not choose to buy, but would like to hear again. Music I enjoy being used to scare off kids, now that is the real sign of aging.