So far, at least, I have not really had to make choices about equipping my army, if I'm using equipment that doesn't require a resource. It's a little tedious going in, every era, and going to every unit and sliding all the new tier stuff over. Is there an auto-upgrade button I'm missing? (I don't mean retrofit, I mean something that just tell's the computer 'edit all unit types to move everything up a tier.)

I'm afraid there is no way, though it would certainly be a great interface addition.

Oh-ooh... that WOULD be nice, wouldn't it?