We would advise a conventional clean at least once a month if not more frequently in harsher weather, while a clean and protection is recommended every three months, although this may depend on the level of protection offered by the chosen product. When cleaning it is advisable to use a soft brush or sponge and a hose or a bucket, and avoid harsh brushes or pressure washers. A dedicated vinyl roof cleaner such as those available from Sonax or Protex will help shift dirt without damaging the surface. As for protecting the roof, ensure the surface is completely dry before applying - we would recommend products from Fabsil, Renovo or Autoglym. You may also wish to consider getting a car cover, as UV light and weather exposure are the most damaging elements.