Reserve service today

Reserve soldiers perform only part-time duties as opposed to full-time ("active duty") soldiers, but rotate through mobilizations to full-time duty. When not on active duty, reserve soldiers typically perform training or service one weekend per month (inactive duty for training or "Battle Assembly") and for two continuous weeks at some time during the year (annual training). Many reserve soldiers are organized into Army Reserve units (troop program unit or TPU), while others serve to augment active Army units (Individual Mobilization Augmentee or IMA), or are simply in non-drilling control groups of the Individual Ready Reserve ("IRR").

All United States Army soldiers sign an initial eight year service contract upon entry into the military. Typically, the contract specifies that some of the service will be served in the Regular Army, or "active component" (two, three, or four years), with the rest of the service to be served in the reserve component. However, some soldiers elect to sign a contract specifying that all eight years be served in the reserve component. Soldiers entering directly into the Army Reserve nevertheless spend a period of initial active duty (five months, more or less, depending upon specialty) for basic training and advanced individual training (AIT) and, like all Army Reserve soldiers, are subject to mobilization throughout the term of their enlistment. Those soldiers who, after serving the active component portion of their enlistment contract, choose not to re-enlist in the active component, are automatically transferred to the reserve component to complete their initial eight year service obligation; this may be in drilling TPUs, an IMA position, or the IRR. After the expiration of the initial eight year service contract, soldiers who elect to continue their service may sign subsequent contracts of varying durations consecutively until they finally leave the service; however, officers may have the option to opt for an "indefinite" contract, in which case the soldier remains a part of the military until they retire, are removed from the service for cause, or are granted authority to resign their commissions.

Officers, Warrant Officers, and Enlisted personnel in the rank of Staff Sergeant (E-6) and above are considered to be on "indefinite" status if they have more than 10 years of service. This means that such soldiers remain in the military until they retire, are removed from service for cause, or are granted authority to leave the service. (This no longer applies to reenlist with an "Indefinite" status as part of the Army Reserve. Memo is dated 20080110 - It is not retroactive.)