"sunnybrooktoyhauler".....If you take care of it, it will last a long time. Use a soft microfiber cloth mitt to wash it, rather than an RV brush. Wax it like you would the rest of the RV.
Before very trip, I either wax it, use 303 or spray Pledge on it. It only takes a few minutes, but the bugs will come right off during or after the trip, depending on how long your gone. Never scrub the plastic to remove anything, soak it and wash it off. Scrubbing will cause hairline scratches that will look bad in a few years.