LOL, you're cutting away very very thin layers each time. So unless you buff it EVERY HOUR of EVERYDAY each year, i would say no it would not be gone after 4-5years. Don't worry mate, your headlights ain't going to run off to anywhere anytime soon! =) Just polish it in nice circles with moderate force, you don't need to apply TOO much force when polishing. Continuous rubs in circles will buff out all the scratches etcetc.