Okay, the professional civilian here, again. While reading more about D-Day and its aftermath, I'm finding that it was policy to constantly infuse already-existing Army units with new people, the units having been worn down by "attrition." I had always assumed that it was policy, once a unit was all torn up, battered up, decimated, that it was pulled back, and an entirely new unit was sent in. And while being pulled out of action, two purposes were served; that of giving the survivors a chance to catch their breath, and giving commanders time to build them back up to...