What does it mean that the patent determines the fee according to the authorization time of the year?

After the patent is granted in that year, the fee shall be determined according to the standards of that year. The patent fees are determined according to the time granted in that year, that is to say, after the patent application is granted in that year, the fees, including annual fees or maintenance fees, will be determined according to the standards of that year, and the amount is usually determined according to the time granted by the patent.