Pay by credit card on the 4th of every month, and credit card spending on the 6th +0 1 is the most suitable. The repayment date of the bank card is 25 days after the billing date, that is, the repayment date of the credit card is the 4th of each month, and the billing date is last month 10. As long as the consumption is made after the billing date of each month, it will be repaid on the 4th of the following month, and the closer the consumption date is to the back of the billing date, the longer it will take to use the funds for free. For example, the billing date is 10 and 168 per month.