Architects, environmental designers, occupational therapists, and human service professionals are variously engaged in efforts to create settings for older persons that better fit their changing lifestyles and abilities. This theoretical article argues that to explain and predict more effectively the appropriateness of the settings occupied and used by their older occupants requires models and empirical inquiries that better conceptualize two areas of inquiry: (a) the temporal properties of environments and individuals and (b) the conceptualization of environmental behaviors or activities describing how individuals use, manipulate, or perform tasks in their settings. The types of constructs and relationships necessary for this inquiry are reviewed and their practical applications considered.