To examine the number of subjective age categories in the post-high school portion of the American lifecycle, adult respondents, selected on a probability basis in Lafayette-West Lafayette, Indiana, sorted cards describing people in terms of major life events and classified them according to age. A nonlinear decrease in the number of age distinctions occurred in the late portion of middle age (46-65 years). The decrease was explained in terms of the developmental cycle of domestic units and age homogeneity of the kinship network.