They had a professional officer corps and drills. In fact, that's mostly what the Spartiate class was really. Since other city states had armies comprised of t

They had a professional officer corps and drills. In fact, that's mostly what the Spartiate class was really. Since other city states had armies comprised of the gentry donning a suit of armor when needed, it made a lot of a difference in that context. Well it turns out that you can have a worthwhile society while also having a professional officer corps and drills, it's just that the Spartans didn't.