I would suggest a roof inspection (get up there and look at it) at least once a month. Look for cracked or missing caulk where water could get it, and any roof damage from tree limbs etc. If any is found, repair or replace (caulk) as necessary right away. Clean the roof at least once every six months. Remember you can clean your roof with a mop, and just soap and water or you can get a special roof cleaner. Using a mop and bucket method lets you clean it without the dirt washing on the sides of the RV (then having to wash the sides to get the dirt off). I would also suggest to keep an eye on the gutter area to be sure it is okay too. I know everyone has their own favorite way to clean the roof so I am sure you will get plenty of suggestions.