The study employs time-sampling data to examine age differences in the quantity and quality of children's and young adolescents' daily experience with their families, friends, and alone. Participants (ages 9-15) carried electronic pagers for 1 week and reported their companionship, location, and affect at random times when signaled by the pagers. Findings show a dramatic decline in amount of time spent with family, with older students reporting half as much time with their families as younger students. Among boys, this family time was replaced by time spent alone; among girls, by time alone and with friends. Affect reported when with family became less positive between the fifth and seventh grade, but was more positive again in the ninth grade for boys. Affect with friends became more favorable across this age period; affect when alone did not vary. These age differences suggest changes in adolescents' daily opportunities for cognitive growth, emotional development, and social support.