You are going to get many different opinions on this subject. I have had Ziebart rust proofing/undercoating done on my last 5 new vehicles and could not be happier with the service. Not one speck of rust on anything since 1992. I do take them back for the annual recommended update ($39+tax at our local Ziebart store) and they come back looking like they were done the first time. It's expensive up front, but it is well worth it in my opinion.