UV Protection

I've been advised that 303 Protectant is the best thing to use for UV protection on my kayak. I'm wondering how often it needs to be applied? I may be a dummy, but couldn't find anything about the intervals for application on their website. Are any of you familiar with this product?
I ordered the 32 oz size because I have no idea how much/how often I'll need to apply it, and need some guidance.
I'm also wondering if this stuff will be sufficient to allow me to leave my yak in the back of my truck. I have a topper, but there are glass windows and the yak sticks out a few feet in the back. Texas sun gets mighty fierce in the summertime.

Rodger

I would "think" two/three times a year would be sufficient.

Don't treat the seat and feet areas. This stuff will make those slippery. Also, it can make your add-on-seat make noise when it rubs.

The plastics used today aren't as susceptable to problems as they used to be! Use it if you want, but its not really necessary any more assuming you don't store it outside in the sun!