First, if the patentee fails to pay the annual fee in accordance with the regulations within the validity period, it will become invalid.
Second, if you pay the annual fee every year, it will last until the patent expires. The stipulated due date is calculated as follows.
Invention patent: 20 years from the date of application.
Utility model and design: from the date of application 10 year.
LZ, please provide your patent application number, and I can help you check whether it has expired.