Trench rotation preserved fitness and taught new tactics

The typical rotation described is roughly five days in a front-line trench followed by a much longer period behind it. Continuous front-line exposure rapidly reduced a soldier's effectiveness. Daily work included watching the enemy, repairing wire, handling mail, maintaining hygiene, and patrolling. Rear-area periods restored fitness, introduced revised tactics, and developed officers and NCOs. The journeys between these activities exposed men to shellfire, and moving at night added the difficulty of crossing damaged ground in darkness.