As for whether it is used or not, it is related to your position direction and account funds.
If you do more, and the stock index has been rising, you don't have to worry;
If you go long and the stock index falls first and then rises, it depends on whether there is enough money in your account to get you through this callback. In case of insufficient funds, you will be urged to pay the deposit, otherwise it may explode;
If you go long and the stock index falls, then you have to be prepared for additional margin and short position, so this time doesn't matter.
The short ones are the same.