How often should you use cleaner/conditioner on your roof?

A good product to use on the rubber roofs is Tide powder without any additives. Getting hard to find, as most Tide comes with bleach and other oxydizers, abrasives, or perfumes, or any combination of the above. A small box of the stuff will last a lifetime. A small amount in a 2 gallon bucket and a soft bristle brush will do the trick. Rinse VERY well. Hose down the side of your rig so streaks don't form with the rinse water. Be careful up there, that stuff is slippery.