Anyone can use the protective film. I didn't use it until after I restored the lenses by wet sanding and polishing though in hindsight it would have been a great idea to install the film from new. The argument for using protective film after restoration is that you don't have to repeat the process or continue with periodic repolishing/refinishing. I simply apply wax over the film when I wax the vehicle, though I have no idea whether that has any benefit to the film. With the film you also get the added protection against chips and lens breakage.