1. For cardholders who have just graduated and started to work, it is most appropriate to apply for a credit card because there is no high input.
2. For cardholders who have worked for about five years and have a certain amount of savings, it is most suitable to hold 1-3 credit cards, which not only has little repayment pressure, but also can make some small money by investing.
3. For cardholders who have worked for many years and have a certain economic foundation, it is more appropriate to have four or more credit cards, and they can have sufficient repayment ability and manage their credit cards well.