Power Buildings

In what sense? Are you referring to resources?

Personally, I always choose the strongest units (of course, based on my personal perception of this criterion), not the most economical ones. Of course, in this case, there are sometimes resource constraints, but this choice doesn't really pose a problem for me. After all, there's a market (where you can always exchange what you don't need for what you do), and there are artifacts. And I know that all the costs and difficulties will eventually pay off. The outcomes of battles prove this! ;)