This tool calculates the age every time you open the record and actually stores the information in the database. Through its right-click menu, you may launch the update of this field for the current lookup.
Since the age information is stored in the database, you may use it in reports, lookups, etc. but don't forget to update the current lookup before you generate reports or lookups to ensure all ages are up to date.
See this video on how to set it up.