Poked around a bit more, the Cost of a Mission is determined by Multiplying all the modifiers NOT by adding them so a +50% and a -50% dont cancel out they are 1.5 x 0.5=0.75 cost modifier (The two "Your State Religion present" modifiers are an exception -15% if it is not their state religion is Added to the -25% if it is your holy city.. before being multiplied) so overall x0.8 Open borders (and a Trade route) My state religion present = 0.85 if its not their state relgion, 0.75 if I have the holy city, 0.6 if its not their state religion AND I have the holy city x0.75 for equal culture (0.5 if their culture/mine=0: 1 if my culture/thiers=0) x1.5 for Security Bureau x(1+Distance to capital/Max Distance) x0.5 Spy fortification x 2 to 0.5 based on total espionage spending Ever against anyone That last bit is key, it means Espionage points 'In the bank' v. a specific civ only do ONE(two) things 1. Give you passive benefits 2. Stop other civs from getting passive benefits v. you They do not help you defend against rival spies or change the costs of your missions. So if you are not interested in Active Espionage missions, send your spy spending against whoever you want to see, because that's all they are good for. If you want to defend against Rival spies or increase the cost of their missions, then spend all your EPs on counter espionage. Otherwise it doesn't matter who your EPs are against, or if you have spent them Actually, EP that you generate before you meet anyone go into the 'Espionage points' genrated Ever So if your civ has been isolated for 100 turns your Palace would still give you 400 EPs in the 'Espionage points ever' so Those Espionage points would still act to help lower the cost for your spies increase your spies chance of survival+success and do the opposite for any enemy spies of course you could never spend those 400 EP, and they wouldn't help you with looking at anyone.