I didn't bother clearcoating them. I figured that by the time the plastic starts to haze again, I'll have accumulated enough rock dings to sand it down all over again.
The polishing doesn't seal at all.
Haha fair enough. I always cleared my headlights after sanding them and it's always last at least a year before needing another light sanding+clearing, but I've only ever used spray can clear from crappy tire.