I go up every time we pull in the slides. We didn't want slide awnings (camp in windy spaces) so I go up to clean off the slides and inspect the gaskets. I also inspect/clean the skylights, roof vents, sink vents, clean out the gutters to insure they work properly, inspect the a/c, and check the antennas. We don't want leaks and it seems the easiest way to avoid them is to frequently check where they might start. We also don't want birds, bugs, or bees building a nest up there. Our last tt didn't have a walk on roof nor a ladder and it was a royal pain to check anything. So we only did it about once every six months, when we had to. Now, going on the roof is like raising our jacks - something we do every time.