Final answer:
A TRICARE beneficiary is considered 'non-grandfathered' if their military sponsor enlisted or was commissioned after January 1, 2018.
Step-by-step explanation:
In TRICARE, the health care program for U.S. military personnel and their dependents, a beneficiary is considered "non-grandfathered" if their sponsor enlisted or was commissioned after January 1, 2018.
Those whose sponsors joined the military before this date would have different benefits or guidelines under TRICARE. It is essential for these beneficiaries to understand this distinction as it affects their eligibility and the specifics of the health insurance coverage available to them.