You should regularly check your statement for any suspicious or unknown purchases. You can also check your account online. If you notice any unusual transactions, check with anyone you authorized to use your card to see if they recognize the transactions. If they do not, you can Initiate a Dispute or contact Customer Service.
Note: Even if you are a Discover Miles Card holder, you should notify Discover if you are planning to travel, especially outside of the U.S.
Learn Moreabout monitoring your account for possible Fraud