Germany and it's predicessor, Prussia, had universal conscription for centuries. In the more modern era the German Army was backed up by "Landwehr" reservists who were liable to recall up to age 45. Some Landwehr troops were used during the Battle of Tannenburgin East Prussia in August 1914. World War I was a meat grinder. They had all the big guns that were available in WWII and it wasn't hard to drop big shells right on the enemy's heads. The number of men who lost limbs or were otherwise disfigured plus the number of men who contracted life threatening diseases amounted toten times the number who were killed. Plenty of men went home to die.