Maybe I’ve just been lucky, or my guys are just stone-cold killers; but I’ve never had any trouble with durability. I don’t think I’ve broken anything other than spears when I’m letting orcs whittle themselves down on a spear wall, and occasionally A sword if I’m going to town with ripostes against highly armored opponents. I always have backup weapons for my guys though (Everyone gets a spear and at least one other weapon).
I’d recommend some Maces and Flails for Orc Warriors once your spearwall is broken.