If I was in your profession, my cut-off would be at 28.
Then again, I haven't fucked an 18 year old since I was 26... and would rather not, for similar reasons that you have.
79-82 Mustangs only had a driver's and rearview mirror as well as 0 cup holders. Ford completely re-designed the interior in 1987 to add ANOTHER ash tray and a FOLDING ARMREST but nooooo cup holders
in the 80's and 90's. But I have managed to modify a Chevy cup holder and put it in place of the useless ash tray with a missing door.
And those buttons? BUTT WARMERS!
(Yes its a mess, I am still working on it.)