Armies have long tried to keep some troops in reserve, both to respond to unexpected enemy action and to rotate in and out of the front lines. Rotations also allow fighting units to "make and mend", to repair and replace equipment, renew supplies and personnel.

In the First World War and Korea, with generally stable front lines, rest periods could be well planned. In the Second World War, troops prepared for years before the Normandy landings, but had little rest thereafter as the pressure was on to keep the Nazis off guard and less able to adjust to Allied advances.

Rest periods brought their own challenges: keeping the men from being bored. Field commanders always looked for opportunities to rest their troops, since a rested unit is a more effective unit.

Life in battle is tiring and fraught with danger. Keeping soldiers in the front lines and at high levels of readiness for an extended period of time becomes counter-productive, and detrimental to high levels of fighting effectiveness. Consequently, units are frequently rotated out in order to provide an opportunity to refresh themselves.

During the First World War, given the static nature of trench warfare, when their regular turn at the sharp end or in the trenches ended, soldiers moved to the rear and out of range of the battlefront for a few precious days of rest. Here they played games of poker, blackjack, Seven-toed Pete and sang of the charms of Mademoiselle from Armentières.

The Dumbells Concert Party is another an example of the impudent, funny and very pertinent entertainment created by these war weary troops. This extraordinary troop show was organized by Merton Plunkett of the YMCA. from soldiers of the Third Division. They delighted the troops with the "Dumbell Rag" and "Oh It's a Lovely War", with their featured female impersonators. Starting out with costumes made out of bandages and lamps made out of tin cans they achieved a level of success that was to survive demobilization and take them to the heights of London and Broadway.

But, time at the rear was not all fun and games. Lightly injured soldiers were attended to and given a chance to recuperate. Reinforcements, to replace soldiers killed and seriously wounded, had to be absorbed and integrated within the unit structure. Lessons learned were reviewed and training in new techniques and tactics took place. Clothing, equipment and weapons were cleaned and maintained, sometimes replaced. A chance for a hot bath or shower was always welcome.

During the First World War several organizations supported efforts to maintain troop morale, notably the YMCA and The Salvation Army. The Canadian Salvation Army's overseas activities were part of the much larger effort organized by British Salvationists. The latter established over 200 recreational huts (often no more than tents), 40 rest homes, and 96 hostels, all staffed by more than 1200 volunteers.

The Canadian Salvation Army sent five military chaplains to the front and helped operate well-equipped huts, canteens, rest facilities, and hostels in Britain, France and Belgium. There, war-weary troops could bathe, refresh their clothing, eat decent food, and prepare themselves physically, mentally, and spiritually for the always difficult return to the trenches. Closer to the front, more Salvation Army officers provided refreshments and amenities, often under dangerous conditions.

As Canadian soldier Will Bird wrote in his classic First World War memoir, Ghosts Have Warm Hands: "Every front-line soldier knew that his true friend was the man in the Salvation Army canteen." The troops coined the affectionate nickname ‘Sally Ann' to describe the Salvation Army while the familiar Red Shield logo – the emblem of its war efforts – also dates from this period.

The nature of the Second World War was much different from that of the First. The operational tempo was much more offensive in nature. While the Royal Canadian Navy and Royal Canadian Air Force were involved in operations almost from the outset, the Canadian Army, aside from small units, and the operations in Hong Kong and at Dieppe, Canadian soldiers were largely training in Britain until the Invasion of Sicily in 1943. When in Britain, soldiers had periods of leave.

Many, of British descent, visited with family and friends. Others would take in some of the sights, even though travel could be hazardous and difficult under wartime conditions in the British Isles. Of course, many socialized with British society and many married British women, who became known collectively as war brides.

However, once engaged in battle in Italy or in Northwest Europe after the Invasion of Normandy in June of 1944, such activities became much more difficult, even impossible particularly for those in the Italian Theatre of operations. However, regular periods of rest, recuperation and re-organization were mandatory, particularly following tough operations such as the D Day landings or at Ortona.

Then, these "rest periods" then took on a frequency and routine similar to that described for the First World War above, except that given the increased range of weapons, improvements to air power and operatives working behind the lines, it was more difficult to get completely out of danger. Almost no matter where Canadians went in the Second World War organizations such as the YMCA and Salvation Army worked to support the troops much as they had during the First World War.