One full year on materials and labor from the date of installation seems to be the industry standard in my area, so that‘s what I offer.
Unless of course I don’t supply the materials, then I offer an exclusive taillight warranty. That being, all work is fully warranted for as long as you can see my taillights.
This is my extended version of the standard tailgate warranty. It gives those value conscious customers a few extra seconds of additional coverage when I leave after sundown. smile