I get mine done at ziebart every year. and it still looks good as new. its only like $120 for a complete and $60 for just the underneath.

 

I've always heard that its bad because it covers up the bolts that hold the tranny pan on and the bolts on the diff. and anything else that you will need to get to in the future thats underneth the truck.

 

I thought you only have to get this done once and forget about it. Does it wear out after a year?

 

I haven't seen it wear out, but undercoating will dry out and crack over a few years, which causes it to hold moisture (in those cracks) rather than shed it. It will also dissolve if you use any type of industrial tar/wax/gunk remover on your vehicle. I use to do this and always had to respray fender wells and anyplace else I would overspray the Zeps while doing my yearly strip.

Not sure if rustproofing cracks or not. The only issue I have had with rustproofing is poor application, blocking OEM drain holes in door bottoms and other places that need to be opened up after the application.

 

I have always done it myself on a new truck. I use ALOT of spray cans and never had any problems. I do it as a sound dampening and chip protector more than anything. It has worked well and the last truck I traded after 5 years looked great underneath.