There are different events that happen at various stages and they are revealed at different times throughout the book.  Age one of course is the naming and the assignment of families.  The "rite of passage" seems to be the receiving of bicycles at age nine- second only to the ceremony of twelve where the members are given their life vocational assignments.  Age ten gives the children different hairstyles.

One of the least talked about, but more interesting ones is the back-buttoning jacket at age four and the front-buttoning jacket at age seven.  The first is to teacher interdependence while the latter shows independence.

Age eleven has only minor changes with new clothing styles and special undergarments for the females.

Three seems at be an important age as it marks correct acquisition of language and dream telling.

Age eight begins volunteer hours.