I feel guilty because mine doesn't get washed often, mainly because I can't decide whether to wash it before we go on a trip or after we get back. Our neighbor across the street washes his travel trailer about once a month it seems but I haven't detected a pattern of before/after. We have a Roadtrek van and it is used as a 2nd car so it doesn't sit under covers ever, it's on the road frequently. And we live in Florida (no road salt or slush), it's mostly white and doesn't show much dirt (maybe I say that to justify not washing). It's also a big chore, involving a ladder, to wash the top and upper sides (another excuse ) So how 'bout it. How often is just right?