I often wonder when is the good time to equip battalions with this. Certainly not during fortress assault, as units are pulverized by turrets before they ever get a chance to hack at things. And you can’t be doing it too early either, because it will cripple your economy to spend twice as much per battalion as before (especially when they still die just as fast). I buy the building upgrade almost every game, but then don’t bother to equip the units with it. For me, the spam is all about expendability, so making units more expensive before I send them to their doom doesn’t seem smart to me. Numbers are better than upgrades. If my economy is in gluttony mode I suppose I could start buying individual battalions the upgrade. But that’s in excess of what it takes to maintain my spam. Anyway, food for thought. That’s what this place is for. I typically don’t buy the upgrade at the unit level, but I would change that if the unit was a level 2.