The simplest explanation is that the bank will check whether you need to raise the limit. It depends on your daily consumption. If your card has an overdraft limit of 5000 yuan, you only need to spend 3000 yuan every month. Even if you go to 100 places and swipe your card 100 times, it's useless. It's best to spend almost the total amount of your overdraft every month. Before long, the bank will take the initiative to help you increase.

I hope my answer can help you!