Death was a constant companion to those serving in the line, even when no raid or attack was launched or defended against. In busy sectors the constant shellfire directed by the enemy brought random death, whether their victims were lounging in a trench or lying in a dugout (many men were buried as a consequence of such large shell-bursts).
Similarly, novices were cautioned against their natural inclination to peer over the parapet of the trench into No Man's Land.
Many men died on their first day in the trenches as a consequence of a precisely aimed sniper's bullet.
It has been estimated that up to one third of Allied casualties on the Western Front were actually sustained in the trenches. Aside from enemy injuries, disease wrought a heavy toll.