T-shirt and sweatpants. Of course, I’d never be able to move back to temperate climes and would have to stay in the tropics. And if it was really one outfit (vs. many copies of the same outfit) I would probably end up going nude after a year-and-a-half or so when said outfit disintegrated into its component threads. So, I’d then have to join a religion, because holy men seem to be the only ones allowed to go buck naked out in the streets without consequence. This is starting to entail more than superficial change.
(Of course, I now notice that the prompt doesn’t say one would exclusively wear this one outfit. But then I think the question becomes meaningless because I think most people — except perhaps a few “fashion influencers” and “celebrities” (quote marks are intentional) — do wear a given outfit over and over [I know I do.])
Point is: it has to be comfortable, not restrict my range of motion, not result in me being a sweaty mess all the time, and allow me to blend.
Tiger Riding for Beginners 