Final answer:
The High Year Tenure (HYT) policy sets a maximum number of years for service members in a rank before they must be promoted or separated. For SELRES E3 personnel, the HYT is 6 years.
Step-by-step explanation:
The HYT, or High Year Tenure, is a policy in the military that sets the maximum number of years a service member can remain in a certain rank before they must either be promoted or separated from the service. For SELRES E3 personnel, the HYT is typically 6 years.