Related: Most people over age 30 should see an ophthalmologist at least once every 10 years. An optometrist is generally fine for fitting glasses, but an ophthalmologist will provide a much more thorough eye exam (as well as updated RXes).

(Exception: If someone's vision is 20/20 uncorrected and they don't have any other eye concerns, this probably isn't needed… until they hit the all-but-inevitable presbyopia, likely around age 40-45.)