why expiration date?

Ever notice all your credit cards are of uniform shape and size? Their dimensions are governed by the ISO 7810 standard, an international standard for identification cards. Banking cards, as well as driver’s licenses and retail cards, follow ID-1 (passports follow ID-3). If your card has a smart chip, it follows ISO 7816, and if it has RFID, it follows ISO 14443.
The expiration date on the card is “fake.” You can still use the card after its expiration date because the card number on your replacement will be the same. The reason why cards do expire varies from company to company but mostly it’s because the credit cards take a lot of abuse and just need replacing (they estimate the magnetic strip is good for only about three or four years of swiping).