Quote Originally Posted by Telys The Conqueror
Aside from using them in the beginning of a campaign the only time I really use peasants is to quell squalor beause the size of the unit is larger than most.
Seconded. Or if I want an army to leave a just-conquered town in a hurry I queue up a couple of them.

Bottom line: They only ever see garrison duty, and that's if I'm desperate to leave.