Promotion from private first class (E3) to specialist or corporal (E4) is usually automatic. When a soldier meets time in grade (TIG) and time in service (TIS) requirements, he is eligible for promotion; soldiers must ordinarily have four months time in grade as a private first class and have served in the Army for a minimum of two years to earn an E4 position. With a waiver, however, a private first class can be promoted to specialist or corporal with three months TIG and 18 months TIS.

Generally, a private first class (E3) must have served in her current rank for a minimum of four months; however, an E3 with three months time in grade (TIG) is eligible for promotion to specialist (E4) if she is granted a waiver from her company first sergeant.

An E3 must have served in the Army for a minimum of 24 months to be considered eligible for promotion to E4. However, if a soldier has been granted a waiver by his company first sergeant, he may be eligible for promotion after 18 months time in service (TIS).

In order to obtain a TIG waiver, a soldier must not have any record of misbehavior or have been punished under the Uniform Code of Military Justice (UCMJ). A set number of waivers is available to each company every month, and company first sergeants may require soldiers to compete for them by attending Soldier of the Month Boards.