Gaming common sense goes a long way.
I always use the Fire Emblem argument here, since it seems like the most casual example.
You can promote units as early as level 10, but if you want the best stats, you should promote at the max, level 20.
Besides, you should at least be able to infer that you're not getting the most out of your character's stats by CC'ing them early.
The one thing Aigis is actually guilty of is not emphasizing the importance of silvers early on.