I think how they hold up depends on where you live (humidity, elevation, salt water). Also, paint color. I live at 5000’+ and in low humidity area. I have eight vehicles that stay outside year around. 3 or 4 go under car covers in the winter because they are not driven on winter roads.
I tend to keep vehicles forever. Of the outside vehicles, I’ve owned the oldest for over 50 years and the newest for 12 years. All are light colored with the exception of a 1970 cj5 Jeep which is bright red. I painted the Jeep with acrylic in 91 or 92 and it’s starting to fade. It’s on the “to do” list to paint and I’ll clear it this time. Paint is good on all the others. I keep them waxed and maintained especially rubber trim
I’ve never had a problem with rust, rot, mold, varmits, and ect., but all my vehicles are steel, no wood.