...which is seldom a problem, since you exterminate towns with large populations. A town with a large population and a big replenishing percentage will recover from an extermination quite quickly, giving you the opportunity to do it all over. If you don't count the small <2000 pop towns, extermination is pretty much a no-brainer, making the "kill more of your own subjects than enemies"-strategy far too appealing. I know few actual empires who's economies revolved around exterminating their capital every 15 year....

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