I can understand why you would want 4 farms, Mines, and the like but 4 Armories? The game will not allow you to train any troops in another armory when one is active. So why was I instructed to build them and I have been up gradeing them all.
You were asked to do things as in introduction to the game, there was never any compulsion to upgrade everything equally.
If you wish, there is nothing to stop you demolishing those you no longer want, or need (you have to maintain at least one),
Though doing so may have noticeable effects on training troops.
You will find at some stages of the game there are advantages in having more of certain buidings.
