I've tried a couple of waxing regimes in the northeast for cars always left outside. I keep them under trees to avoid UV effects. Just have to be more careful about rinsing off organics and bird poo a few times each week.
1. No waxing on a 22K mile car - by the time I sold it 8 yrs later with 230K miles and mechanically hurting, the paint had no shine...but fully intact. No rust. For that car, it didn't affect the value.
2. Same exact model car as before, this time went 9 yrs, washing or rinsing about monthly, and waxing 2X per year. That paint stayed very nice for a 16 yr old car when it was sold this year. Once the generic wax stops beading up well, it's about time for a 6 month application (May, Nov). Never used polish, buffers, clay bars, or anything beyond a towel and a cleaner wax.
I now stick with regimen #2.