Depending on where a person lives, a person may or may not be required to serve in the military. In Tridon, peasants are not required to serve in the military, but can sign on willingly. The nobles and merchants try hard to have a child or children as Knights or Knight Captains, since it is very prestige to be tied to one or the other. A lot of second son peasants who will not inherit the farm from their parents join the local militia or the army of the House they live by.
In Ariella it varies. If the person lives in the Empire, then a male of 18 years of age must serve 2 years in the military. Women may join, but few do and they are not required to. After the service time is up they may return to their homes, though if they are good enough the legions will try to entice them to stay.
Akicitia in Ariella do not have a standing army, but every adult, male or female, are trained to defend themselves and protect the village.
Elves on either continent do not have a standing military, but usually families, whether rich or poor, like to send one child to be trained in the martial arts so as to help with defense if need be.
Dwarves have a five year mandatory service for both men and women, though they engage very rarely. The military practices their skills by protecting the stoneholds from ogres and the like, which bothers them often.