- The military reserves are groups of citizens within a country who carry on dual roles as military personnel and normal working citizens. Reservists are usually not on active military duty but work as civilians with periodic military training. The reserves are generally meant to act as an emergency force that can be employed to immediately inflate the size of the country's standing army should the need arise, as it would during an invasion or a large-scale war. Using the reserves in this way saves the costs associated with maintaining a large standard army, but makes a larger army available.
- In the U.S., the military reserves are volunteer forces that train regularly, often one weekend a month. Reservists are often called upon for part-time services and are also assigned full-time duties on a rotational basis. Since the war in Iraq, military reservists have been called upon to serve full time in greater numbers to fulfill the need of additional occupation forces. Reservists are more commonly employed in a support role for the standing army, while full-time military forces focus on combat roles. This is not to say reservists do not see combat, however; a large number of the reserves are former full-time military personnel who may have as much or more experience as soldiers in the standing army.
- The main benefit of carrying on a military reserve program is having a force of trained personnel who can be added to the standing army should the need arise. By allowing the reserves to participate in the country's economy rather than keeping them as active military personnel, the government can take in more taxes and pay fewer military salaries without risking a shortfall of manpower if war breaks out. With large reserves, it can also relieve units more quickly, so the burden of service is spread around to a larger group so units can get rest and leave time. One drawback of using reserves is that some members of the reserve force may have never been in action and may be undertrained with the most current military gear and tactics. Also, the best equipment may not always be available to reserve forces since standing forces usually take precedence. Finally, since reservists carry on civilian jobs and lives, being called up for service can interrupt personal affairs, resulting in lower morale.
