"Fast forward and fast out" usually refers to the rapid inflow and outflow of funds from a customer's bank card in a short period of time. This behavior may attract the attention of banks, because it may imply some unusual trading behaviors, such as credit card cashing or money laundering. The bank's fast-forward and fast-out is usually no more than 24 hours, and the bank flow of fast-forward and fast-out and instant deposit and withdrawal is generally not recognized by banks. Therefore, if users want a reasonable bank flow sheet, they need to ensure that the money is stored in the user card for a longer time. The bank deposit time shall be no less than 24 hours, and the interval between deposit and withdrawal shall be as long as possible, so as to reasonably avoid problems in the process of bank deposit and ensure the effectiveness of bank flow. Banks can check whether individuals have a stable income and the ability to repay debts through running water.