Do ear muffs wear out?

[10-Ring]

I've been using my current pair for 2 years now & they still seem to be fine, but I'm curious. Does the foam stop being effective at noise reduction?

 

[Ledbetter]

Usually they're good until they stop sealing around your ear due to deterioration of the soft plastic part that touches your head-bone.

 

[10-Ring]

Thanks...makes sense why doubling up w/ ear plugs is so effective to counter any imperfections in that seal