I conditioned my RV's roof every 6 months. And, manually wax its sides with NuFinish product as well. Did the work myself to ensure if was done right - and I quality inspected with my own eyes. I also manually wax my Tow Vehicle as well. Was all this a waste of time and/or dollars? I don't think so. Had that RV for 15 years without roof problems. And, it had very few black streaks down its sides as well. My neighbour would often lecture me about wasting dollars. Yet, his RV had roof problems in 10 years. Then, total re-skin in 16 years. And, the sides of his RV has permanent black stains. Yet, he still lectures me about was of time and money (for materials only) today. Ya. He's a funny guy... In my family, we treat / take care of things like we want them to last forever....