this thread is getting good
Toward the late game, libraries are sort of worth it, as 25% more commerce is a lot once your city is working 12 towns. But the point is, before then, the hammers are a lot better spent on axeman... almost all the time. I still believe that the barracks and courthouses in every city can't go wrong though.
courthouses can be totally useless, believe me (low number of close cities) for more than half the game (in dates, not in turns).
And barracks can be a real waste : is it better to have 1 promoted axe or 3 axes?
Is it better to have 2 catapults or a barracks? I very often build catapults in commerce=barrackless cities. Those are suicidal units anyway, and the difference isn't worth the building.
We should be aware of what we're doing. When we play in "automatic mode" (= saved queue, or such things), we must be aware that it's very often suboptimal. How important is it to play an "optimal" game? IMHO it isn't a big deal, except you won't climb levels as fast as "optimal seekers".
When I put my brains on the task, I see which buildings fit in my global strat and which doesn't. It's not tedious. In fact it's the fun part, to be selective.
Still, I very much always play games based on "should do" (= no conscious maths) or "could be fun" (= trying exotic strats).
I am aware I'm not getting optimal results from this, but I still play cIV and warlords for my pleasure after more than a year
. I (almost) didn't play any other game since cIV is out.
Optimal? none of my business