This is not necessarily the case. The bank does not require cardholders to have their balance reduced if they do not apply for installment. There is no direct connection between the two, so there is no need to worry about the balance being reduced if they do not apply for installment. Of course, you should keep your credit card in good condition in advance. You can use your credit card more often to make purchases, don't use the card illegally, and pay back your money on time. Basically, if you do these things well, you don't have to worry about the bank reducing your credit limit.