"We don't offer warranties on any of our products. There are many factors that play into how long they'll last. The materials we use are rated for ## years, and we've seen them last much long and occasionally barely hit that mark. On the off chance that something does go wrong with an install, we'll typically know within a few months. At that point, bring it back in and so we can determine if it was a fault in the material, install, or maintenance. From there we can have make the changes necessary, possibly at no charge, if the issue stems from the material or installation."
If they push, we ask how long they plan to have the vehicle. Typically it's only a few years "okay then by the time the graphics may fade or crack, you won't have it anymore. If it's longer, we say something about how it'll have made them enough money to put new graphics on anyway.
I've never had to redo a vehicle. Rarely have we even been asked about a warranty.