Soldiers in the Army must serve 84 months to be eligible for promotion to staff sergeant. Ten months of service is required at the sergeant level. The Army allows for early promotion in the secondary zone. The secondary zone is for exceptional soldiers recommended for promotion by their commanding officer. A minimum of 48 months of service with five months of service at the E-5 sergeant level is required before promotion in the secondary zone. In addition, all soldiers must have a 12-month service requirement remaining to be eligible for promotion to staff sergeant.
Marine sergeants must serve a minimum of 48 months with 24 months at the E-5 sergeant level.
The Air Force requires three years of service with six months at the senior airman rank for promotion to staff sergeant.