Not really other than refraining from parking under trees that drip sap (like pines). You do need to physically get up there at least yearly and check the roof caulk around all the seals and skylights. The main point of entry for water is the roof and where it seals to the edges.
IO don't do anything to my roof at all. Just check the caulk twice a year, but I park my unit inside when I'm not using it and in the off season too.