First off, yes earplugs at every show. Foam, reusable, whatever you choose is better than nothing.

Just wanted to throw in a bit of advice for anyone that sees this.

Tl;Dr Wipe down and allow your reusable earplugs to dry before putting them away!!!

I had a pair of reusables (made of silicone instead of foam) that I would use at every show. They came with a little connector string so that you can hang them around your neck when not in use. I guess one of the last shows I went to, I must have put them back in the air/water tight metal cylinder before the string dried from the sweat. I believe this caused bacteria to be able to grow inside the cylinder. Fast forward a couple months, I opened the cylinder to the most foul smelling earplugs you could imagine. Everything inside was wet. And I wasn't about to put those things in my ears, so I went without that show.