My experience is bookkeeping, recording every consumption, setting a maximum consumption at the beginning of each month, and then recording it after swiping the card. I can use personal accounting software to see how much credit is left, which belongs to internal control. If online banking actually has internal control over purchases and purchases, the consumption quota of online banking is generally set at the time of application for opening. For example, it can be used to control how much it can't exceed every day and how much it can't exceed every time, which belongs to external control. Another good way is to use only one credit card every month, which is also convenient for repayment. Try not to apply for too many credit cards, which is very laborious to manage.