What product do you use to rust proof with? How often does it have to be reaplied? What is the warranty?

What warranty do you get and how often do I have to recoat it to keep protected

If it's not line x. It's basically a oil compound that kinda soaks into the metal and stays good for up to a year. If its line x it's good for the life of the vehicle. Just costly.

They don't rust proof

We use Zebarts or LineX.