[Tcoat]

I spend 14 hours a week on highways frequented by gravel trucks and my front bumper looks like it was hit with multiple shot gun blasts. I just leave them. Back last September about 2 weeks after I got the car I took a rather serious high velocity rock hit to my front fender. It left a paint chip about a 1/4 inch around. As I am a curious sort of guy I have left it untreated (I do not plan to keep the car for years and years) just to see what happened. So far it has gone one year, including a very salty winter and there is zero sign of any rust and the paint around it has stayed intact.
People seem to think all cars are 1986 K cars and the least bit of exposed steel is a rust hazard. Not true anymore with the way they treat it before paint. Still better to fix chips on the steel sections of course but you car isn't going to rot away in 2 years if you don't.