For porting I generally wear the red ear muffs. At the races I use the electronic models that attenuate everything over 85 DB's. I really like them as I can hear conversations.
I worked at machine shops in the 60's as a burr hand, (machine parts finisher "A") when I was in college. We did not use any type of ear protection when using air die grinders, or anything else for that matter. I have permanent hearing loss in my right ear as a result of not using anything. I had the die grinder over my right sholder and the exhaust was at my right ear. In the 60's we did not know about hearing loss/damage. Management might have known but the burr crew did not, that is why I say "WHAT" a lot.