Military reserves

A reservist is a person who is a member of a military reserve force. They are otherwise civilians, and in peacetime have careers outside the military. Reservists usually go for training on an annual basis to refresh their skills. This person is usually a former active-duty member of the armed forces, and he remains a reservist either voluntarily, or by obligation. In some countries such as Israel, Singapore, Serbia and Switzerland, reservists are conscripted soldiers who are called up for training and service when necessary.

History
Historically reservists first played a significant role in Europe after the Prussian defeat in the Battle of Jena-Auerstedt. On 9 July 1807 in the Treaty of Tilsit, Napoleon forced Prussia to drastically reduce its military strength, in addition to ceding large amounts of territory. The Prussian army could no longer be stronger than 42,000 men.

The Krümpersystem, introduced to the Prussian army by the military reformer Gerhard von Scharnhorst, arranged for giving recruits a short period of training, which in the event of war could be considerably expanded. With this the reduction of the army's strength did not have the desired effect, and in the following wars Prussia was able to draw up a large number of trained soldiers. By the time of the Second Reich reservists were already being given so-called 'war arrangements' following the completion of their military service, which contained exact instructions relating to the conduct of reservists in time of war.

Germany
Every conscript which has served at least a day in the Bundeswehr is a reservist, unless he is declared ineligible for military service or has made a claim of conscientious objection. Soldiers of enlisted ranks with a limited contract (either 4, 8 or 12 years) or professional soldiers, who have filled their tour of duty, are likewise part of the reserve. This is also the case for women, but on the basis of the Soldatengesetz (Eng: Soldier Bill), not the Wehrpflichtgesetz (Conscription Bill). Every soldier follows his rank with the initials "d.R." ("der Reserve" - "in the reserve"). So it does not affect whether the soldier is called up, placed in an inactive formation, or not. Only professional soldiers use the appellation "a.D.d.R" ("außer Dienst, der Reserve" - "out of service, in the reserve") after the end of their service. All others (part-time soldiers and conscripts) strictly use "d.R." until the end of their lives.

Reservists are an integral part of the Bundeswehr. They are essential for the capability of the armed forces in time of war.

Reservists can be active in the Bundeswehr in addition to their mandatory service. This mostly happens through (mostly voluntarily) military exercises or official events. Apart from that the Bundeswehr organises reservist unions as particularly representative supporting organisations of "voluntarily reservist work".

Eligibility for compulsory military service for soldiers and other servicemen of low rank ends at the end of the 45th year of age. Thereafter the conscript is no longer part of the reserve. Despite that the appellations "a.D." and/or "d.R." may still be used. Conscription for under-officers and officers lasts until the 60th year of age. Until the 32nd year of age every conscript is subject to military inspection.

Recognised conscientious objectors, who have competed their civil service, are nonetheless part of the reserve and in the event of war will be given a suitable non-combatant role outside the Bundeswehr, such as emergency medical services, clearing debris or minesweeping.

All conscripts who have not done their service belong to the Ersatzreserve (replacement reserve).

Singapore
All male able-bodied Singapore citizens and second-generation permanent residents upon reaching the age of 18 are required to serve National Service. They serve a two-year period as Full Time National Servicemen (NSFs), assigned to the Singapore Armed Forces (SAF), Singapore Police Force (SPF), or the Singapore Civil Defence Force (SCDF).

When a conscript completes his full time service, he is considered to be "operationally ready", and is thereafter known as an Operationally-Ready National Serviceman (NSman). NSmen are the equivalent of other militaries' reservists. The difference in nomenclature is because these NSmen will form the bulk of the Singapore Armed Forces in times of war. The term Operationally-Ready National Servicemen conveys more importance than the reservists. Similarly, Operationally-Ready NSmen of the SPF and SCDF are available to be called on in time of need.

Spain
Reservistas voluntarios (Volunteer reservists) provide the Spanish armed forces branches of qualified professionals essentially required for each army. After four weeks of training the reservists acquire the degree of soldier, sergeant or junior lieutenant (alférez).

United States
All five branches of the United States armed forces have their own Reserve Forces, whose reservists can be called upon to serve anywhere at any time:
 * United States Army Reserve
 * Marine Forces Reserve (U.S. Marine Corps)
 * United States Navy Reserve
 * Air Force Reserve Command (U.S. Air Force)
 * United States Coast Guard Reserve

There is also the United States National Guard, which is under dual Federal/State control, and is traditionally intended for homeland defense and domestic disaster relief (although large numbers are currently deployed in Iraq, and as such the distinction between National Guardsmen and Reservists has become blurred). The National Guard is divided into:
 * Army National Guard (U.S. Army)
 * Air National Guard (U.S. Air Force)

During peacetime Reservists and National Guardsmen spend one weekend a month, two weeks a year annually in training.