I often wonder the same thing. Here in south Tx the sun is brutal. There are so many different products that it definitely makes it hard to choose and try them all. I've had a few favorites forever that always work really good,and I'll rotate them around. I'm not a big fan of "protectants",they seem to dry rot exterior plastics and rubbers eventually. The absolute best thing I've found to use regularly on exterior plastics and rubbers is Eagle One Nano Wax spray. I use it on the entire exterior. Paint,plastic,rubber,glass,etc. On the interior I use nothing but leather conditioner (leather seats,leather trim,leather steering wheelleather shift knob,all interior plastics and vinyl,etc). Armor All Leather Protectant spray,Mr Leather,and Lexol have been in my rotation for 20+ years.