Originally Posted by barry
Personally I think I will change these plastic vents every four or five years as they get so brittle with age and one only has to hit it while washing the trailer to induce a crack.
There's a saying "Don't fix it, if it ain't broke." While I'm definitely a huge maintenance freak, I think replacement like this is a bit overboard. You can extend the life of plastic parts... paint the plastic with Fusion paint (http://www.krylon.com/products/fusion_for_plastic/
) and yes, keep it waxed. A good marine wax also contains particles to protect from UVs. As you know, UVs are killers of plastics.