I use a little cleaner wax like Meguiars on any stained areas like where the gutters cause streaks. If it's worse than that or oxidized then no wax will help, out comes the polisher and some cutting and polishing compound.
Everything else gets a quick shot of turtle spray wax. Including cars, trucks, cargo trailer, Sno machines. That stuff is best thing since beer in a can. No streaks, doesn't whiten black trim, works on Windows and it actually lasts a reasonable amount of time.
It's more expensive than a can of fleet wax that lasts a long time, but I can wax a vehicle in barely longer than it takes to wipe it down and much less effort.