Keeping a card means using credit cards from other banks to fill the gap when your credit card overdraft is about to exceed the bottom line. This is using a card to keep a card.

To put it simply, you use card A to make purchases, and use the credit limit of card B to repay the money owed to card A in the future. When it's time to repay card B, I use the credit limit on card C to repay card B. When it was time to return the C card, I used the A card to return it.

Extended information:

The way to maintain a credit card is that the cardholder must first apply for two or more credit cards.

Then stagger the repayment dates of several credit cards. Use the first credit card for daily consumption. Before the repayment period, use the second credit card to overdraft and withdraw cash to pay off the debt of the first credit card, and so on. By analogy, several credit cards are overdrawn in rotation.