Apprentices are youths who are learning a trade. Considered the third stage of a person's life, it is generally begun when a youth is between 12 and 13 years of age, children of 14 and over are considered too old to begin an apprenticeship. During these years a person should be learning a trade or otherwise preparing for adulthood. When an apprenticeship is complete the individual becomes a journeyman.
There are several exceptions to all this; some trades compress apprenticeship to three years, others extend it to nine. The major exception, though, is that the city guards of all three Ethshars take recruits of sixteen or older. Some traditionalists consider this perverse; actually, it's a matter of practicality. Men younger than that don't have their full growth; even if they're already large, you'll have to keep re-outfitting them. And without this safety valve, you wind up with rowdy, bored young males of sixteen and seventeen who either never apprenticed or were thrown out raising hell in the streets. Better to put 'em to use in the guard.
One expression among Ethsharites is that a precocious youth is "apprenticed on his twelfth birthday." As this is the first day they can legally be apprenticed it means that the youth, or someone steering their life, has made the decision what they will do with their life and moved forward with it as quickly as possible.
By tradition, all youths have the right to demand some form of patrimony, a means of arranging to support themselves, between their twelfth and thirteenth birthday. While the practicality and application of this depends on the wealth and situation of the family twelve year olds will receive a lot of goodwill if they are trying to to prove themselves. Individuals who choose, or are unable, to move in to the traditional mercantile track of apprentice, journeyman, master generally find their options somewhat limited. A common practice among families with wealth and status, particularly for women, is to arrange a marriage to someone with money or a promising tradesman. Individuals from families with businesses can sometimes, if the business is large enough, live off of the work of the employees and simply manage the business rather than learning a formal trade. Individuals without some sort of patrimony generally find themselves at the lowest level of society unless they can manage to find a niche.