[Alneyan]

The game will tell you once the conditions have reached the best level. I haven't found them to have much use though, as it only alters reproduction, and rather slowly at that. (The worst the conditions are, the slowest it will go, as it effectively multiplies rather than add)

If I do want to give my Empire a nice boost, I would much rather build Atmospher Converters, as the effect of these facilities is much more marked. But obviously, it is only if I am patient enough to wait for thirty turns before the atmosphere is changed.