Early in this one game i had 5 military units and 3 workers. My unit maintenance was 11g per turn. So i thought 1g per military and 2g per civilian unit. Then i saw this bit about supply in the military overview. What does that mean and how does it affect unit maintenance?
Workers cost 9-11 gold for a pair. If you liberate (delete) one, you get no benefit. Liberate the second, and you'll get the 9-11Gold reduced from your maintenance costs.
Military seems to work the same, but I'm sure that it's not every pair. Riflemen come in a quartet (retire 3, no benefit. Retire the 4th, 9-11 gold).
I wasn't watching too closely, but I believe Barbarian Brutes cost 6G each (they may have been paired, I can't remember...).
Also, I don't know if death during combat counts towards the unit maintenance reduction.