Just for the sake of discussion. If buying used; I’m going to suggest states that get the least sun, are flat with moderate temperature swings. Within that state, the car that’s maintained well, driven the most considerately and always kept under cover (not heated) when not in use. Of course you need a good car to begin with. A well maintained Yugo, may still not be a good buy.
Florida being the flattest may give you the best used mechanics, Washington having the least sunshine and moderate conditions may give you the least chance for “aging”.