When buying units (infantry, ground, air, sea) it states casualty rate:very low, low, medium, high.
My question is: What does the level of each rate means? Which level are used most when fighting/raiding/etc.?
For example: If I were to purchase infantry units with higher casualty rate, is that going to be used/dropped out of your inventory? Or vice versa.
Can someone please clarify that to me? Thanks!