No, you don't have to pay off all American Express card every month. Most Amex credit cards allow you to carry a balance from month to month, requiring only a monthly minimum payment to keep your account in good standing.

Whether you have to pay in full depends on the specific card type and your settings. Most Delta SkyMiles Credit Cards (Gold, Platinum, Reserve) are traditional credit cards that allow you to carry a balance from month to month, though you will be charged interest on any unpaid portion. However, many of these cards also feature the "Pay Over Time" option. If this setting is "On," you can choose to pay only the "Minimum Payment Due" and carry the rest with interest. If the setting is "Off," you are technically required to pay the full balance of eligible charges by the due date. For the best financial health and to avoid losing your earned miles (some terms allow Amex to forfeit miles if a payment is late or missed), it is always recommended to pay the statement balance in full every month.