SSSHHH… BE QUIET! I'M HUNTING FOR CITIES
City capture works differently in Rise of Nations when compared to its cousins driven on the turn-based gaming model. For example, in Civilization II you either completely took over all parts of a city or, if the city size was "1" (10,000 people), it was leveled it to the ground. This method was as reliable as clockwork. In the real-time environment, it's not as cut and dry a method.
First, on city size: there are three different categories based on population. They are small, large, and major (the latter of which only comes into consideration beginning in the Industrial Age). No more numbers designating a precise census of the masses. Nonetheless, as a city grows it carries with it more influence and might both within and outside of its nation (just as in CivII and similarly themed titles). As eluded to earlier, when one attacks a city and drives out the enemy, you begin to soften the political center to embracing your ideas, values… and control. When you have obtained complete run of a city including any and all of its structures, you can elect in your infinite wisdom to burn some or all of it down if you care not to give it any further consideration.
However, there are numerous advantages to holding onto the cities you acquire and investing in them from there; to that end, you inherent existing infrastructure and only inherent the costs of their upkeep – not their initial construction investment. There are a number of factors to balance in reaching a decision. If you think you can hold your newest acquisition(s) for a period of time, you will probably want to keep it tugged close to your heart and purse strings. If you feel you cannot hold it, though, you will probably want to ignite a blazing inferno to cut your loses to a minimum. An additional variable to add to this formula is that any attempt at scorching a city to ashes is that the process is not simply a matter of a few keystrokes generating an instant result. Not only does it take time to dismantle a city, it also takes time to clean up the inevitable mess afterwards. In this circumstance, ask and answer the following “check and balance” question: can the enemy foreseeably reclaim these spoils… or anybody else for that matter?
Rise Up: Reynolds On RoN 
