The free units are often available before you can build them and as a result very dominant, the great general bonuses deserve their own thread for a better discussion. There is a poll of most popular retirement bonuses but if everything gets boiled down to a popularity contest there would be no point in posting any comments in this thread. The opportunity cost argument has been thrown around so much in this thread that I am bored with what is a very subjective term and gets used as an "I win the debate" button more often than not. You value envoys more than I do for example, so would place a different value on the opportunity cost (again probably a thread just discussing this would be more useful). You would have to compare strategies.along with opportunity cost, e.g. encampments can be produced earlier than CD so research and civics would also need to be part of that discussion. When I spammed encampments I got so many generals I could afford to expend them for the bonuses without hurting my conquering, and of course I was denying those generals to the AI. I even used 1 just to explore with.