Ear protection. Whether it’s faulty earplugs that result in a massive class action lawsuit 4 years down the road or the cigarette butts you police called earlier, something is better than nothing when you’re in loud environments. Unless you’re in real combat. Real combat, you ditch that shit and hope for the best, but it’s required for training because “we train like we fight” or some shit.
I forgot to put my ear pro in, once, and realized that I might, actually, already be deaf.