You have either been asked if nails need the chance to breathe or have asked someone if your nails need to breathe. It is a very common question.
The truth is they really don't, they get the nutrients, oxygen, and anything ese they need from your bloodstream. Coatings on the nail from nail polish to enhancements are actually meant to protect the nail. If you find that wearing coatings on your nails are causing them to become overly thin, weak, and progressively damaged, unfortunately this is not due to the product.
Damage to the nails is caused by improper application OR removal. Before you point your finger at the person applying the nail coating, make sure you are not the culprit. Do you take your side of the nail care partnership seriously? Are you doing good home care - using a quality oil daily that has a carrier molecule in it allowing the oil to penetrate the coating when used faithfully? Wearing gloves when using household cleaners, including cleaning wipes - your nails are made of keratin just like your hair, a good rule of thumb is if you are not willing to rub it all over your hair then you should wear gloves when using it to protect your nails. Wearing gloves when gardening or handwashing the dishes. Making sure the length of your nail's free edge does not exceed two thirds of the length of your nail bed, that your nails are not too long for your job or activities, picking at your coatings, picking or chewing off your coatings, peeling off your color or other nail coatings. Any of these thing can cause damage or even trauma to the nails!
Hopefully this all gives you some insight into the reason nails do not need to breathe, and what could be the real reason your nails are getting damaged. There is also the possibility you were born with thin, weak nails and in that case a nail coating is going to be a great partner for your nails to hep them get just enough strength to maintain an average length! Take care out there and enjoy your happy non-breathing nails!