Is rust proofing worth getting in a new car?

It depends on where you live, forget it in Arizona, New Mexico and states with a similar climate. I on the other hand live in Ohio and have worked on cars for about forty years. Here rustproofing went out of favor back in the eighties because the factories made big improvements in their corrosion protection. Apparently that has changed. I am sliding underneath cars and trucks that are only three and four years old that already have numerous rust spots that will clearly get bigger. I go under five and six year old cars that have real rust problems. In this part of the country brake and fuel lines are big business, but it is a business that I would rather not have. If you do get rust proofing make sure that the car is completely dry before the coating is applied. I have seen dealerships wash a car and immediatly spray it, sealing some water in, not out