No one time application lasts forever. "Permanent" rust protectants typically offer a warranty for a maximum for 10 years. This means such systems can only delay serious rusting. Furthermore, annual inspections or touch-ups typically are required to keep the warranty valid, so there is no difference as far as the "convenience" factor is concerned. Rust Check maintains a high level of corrosion protection by completely retreating your vehicle very year. By doing so, Rust Check can offer a lifetime warranty - we will protect your car "forever".