The reserve units bolster military readiness.
The reserve units bolster military readiness.

The U.S. military is the strongest in the world, and much of that strength is owed to its personnel. In addition to the active units of the Army, there are retired reserve and inactive reserve units composed of service members who have left the military but may be called back to duty under certain circumstances.

Inactive Reserve

The inactive reserve is more combat-ready than the retired reserve. Members are not active duty but may still receive pay for other obligations they fulfill, such as being committed to be called up for muster duty or submitting to annual physical and medical evaluations. Membership is irrespective of age or experience as opposed to the retired reserve. Members may also continue to undergo inactive duty training and may eventually change their status to retired reserve.

Retired Reserve

The retired reserve contains the military's retired members who have put in at least 20 years of active duty service. These members are not discharged and, as such, may be called back to active service under certain circumstances, such as war or national emergency. Only retired reserve members who have not yet reached age 60 and receive pay can be called up.

Function

The retired reserve is mostly made up of combat support units, such as medical personnel and equipment technicians, although it does count combat units among its ranks. The inactive reserve is more generalized, involving a range of servicemen and women who are expected to fill gaps in combat, combat support and non-combat roles should the Army need to draw on its reserve ranks.

Other Reserve Units

A number of other reserve units serve in the Army. These include the standby reserve -- made up of both active and inactive members -- and the individual ready reserve, which has no training obligations -- except in times of emergency or war -- and does not receive regular pay.