I'm trying to figure out the best size for a standing defense-only army in peacetime, if I'm aiming for a non-Conquest/Domination win. (premise: average difficulty level) In past versions of Civ, I've had a rule of thumb of two of my best units in each city, which was usually enough to slow down attackers at the beginning of a war while I ramped up military production if necessary. IIRC, this was also usually enough to dissuade most other civs from attacking unless they had a major tech advantage. In Civ IV, I've read (and experienced) that military might plays only a marginal factor in the decision of other civs to declare war on you. What "rule of thumb" do you have for the number of military units per city during times of peace (and assuming you're not planning war)?