Ear Defenders are a must (in my opinion) for the modern person looking for serenity
Especially if you are surrounded by noise pollution or want to get away from noise
Positives about Ear Defenders :
Instantly 'escape' (to a degree) noise pollution around you
Use them to reduce noisy neighbours, on public transport, anywhere you want 'audio peace'
They have many price ranges but the cheap ones are very cheap !
Also I find I can squeeze my small in-ear headphones underneath so that I can listen to audio of my choice.
Negatives about Ear Defenders :
They can be uncomfy over a period of time (weight on the head etc)
My set does not stop all noise (but does well with impact noise and greatly reduces annoying sounds)
Perhaps they are designed not to stop all noise due to safety concerns
My fullset size are a bit bulky. For instance can't sleep with them on.
Overall, I think a set of Ear Defenders is a quality of life investment for anyone.
Amazon USA search 'ear defender' : link
Amazon UK search 'ear defender' : link