Some of us would like to keep our eardrums in working order. To do that you can avoid concerts and the like and it also helps to have a pair of earplugs handy, but it’s not always convenient to carry them around. Unless you could fit them in your wallet somehow, like these RNID plugs from designer Shing Lo.
They even come with a set of rubber gaskets for a tight seal in your ears. Plus you can put them back on the card for storage. If these ever show up in the market, they would be pretty popular as a disposable and convenient product.