The high degree of interindividual variability of processes of aging is mentioned and biographical factors influencing age stage and processes of aging were analyzed. A review of empirical biographical studies is presented, which emphasize a conceptualization of behavior in older age at the interaction of past experience, current situation, and future time perspective of the individual. As an example it is discussed how the mother experiences and reacts to her last child's leaving home ("empty-nest-reaction"). An analysis of the data of the BLSA (1965-1977) demonstrated many patterns of change. It could be shown that there exists consistency as well as variability in personality variables. It could be shown that the biographical and social context was closely related to these interindividual differences in consistency and change. Conditions are multidimensional rather than uniform. This high degree of interindividual variability of change calls for a differential gerontology.