Credit cards have expiration dates for multiple reasons, but the first thing to understand is that they apply only to the physical card, not to the account. Your card will expire, but your account will remain open.
If your card expiration date is coming up, expect to receive a new card a couple months before the date. If the date is imminent and you haven't received a replacement card yet, contact your issuer.
In general, your card is valid through the month identified in the expiration date. If the expiration is "07/21," for example, then it should be good through July of 2021. When your new card comes, activate it, then destroy the old card.
Here's why credit cards have expiration dates.
The expiration date provides a degree of protection against fraud. For transactions when the card isn't present — such as purchases online, by phone or through the mail — the expiration date provides an additional data point that can be checked to make sure the card information is valid. If your card number has been stolen but the thief doesn’t have the expiration date, it may not be possible to make charges on the card. Putting expiration dates on cards also prevents old and perhaps forgotten cards from being used if someone else discovers them.
Credit cards get heavy use — in and out of the wallet or pocketbook, in and out of the chip reader, swipe after swipe of the magnetic strip, or magstripe. That takes a toll on what is a fairly flimsy piece of plastic. The magnetic strip can get dirty or scratched. The card itself can crack and split (especially if you keep it in an overstuffed wallet that you sit on all day). The simple fact is that credit cards don't last forever — and you don’t want to be stuck somewhere, needing to swipe your card, and have the magnetic strip give out. Getting a fresh card from the issuer every few years prevents that from happening.
A gentle reminder
Perhaps you have a credit card you don’t use that often. Around the expiration date, you’ll get a new one in the mail. It allows your card issuer to give you a nudge — Hey, remember our card? If new features or perks have been added, it's the issuer's chance to re-market them to you.
Branding and marketing
Credit card companies change their branding from time to time. Cards that used to say "Citibank," for example, now all say "Citi." If a company has totally revamped its logo, branding or card design, expiration dates ensure that those elements eventually reach every card in the "fleet."