Polyester, info the sales guy didn't mention: If you are using a Polyester product in a potential barefoot area (i.e., bedroom, bath entrance, kids' room) there is a problem with the natural oils from your body. Polyester products then to lose their luster (color sheen) and show those traffic areas where little and big feet have walked a path. The oils seems to break down with time fiber structure and leaves a dull, crush looking path. I have study many carpets and their fiber structure, and this is the only major down fall with polyester products. Suggest, everyone to wear socks. Also, protect any entry areas from outside oils carried on shoes. (Kitchen grease, Garage, asphalt drives, etc.) Suggest walk off mats at these areas.