Geographers, including those interested in the relationships between health and place, have made important contributions to how, when, and where humans are exposed to and influenced by different spatial contexts. Using detailed and sometimes real-time spatial and temporal data, geographers have enhanced our understanding of how people move within and between different social and physical environments and the implications for health outcomes and behaviors. Yet almost all of this work focuses on spatial–temporal mobility over short time periods (e.g., day, week), and there has been little effort to understand the extent to which people are exposed to different types of places and environments over their full life span. This article examines the analytic possibilities of, and technical challenges to, incorporating this uncertainty into a life-course framework to better understand (1) the accumulation of environmental circumstances over life and (2) whether there are critical periods during life when aspects of place are particularly pertinent in understanding health. It is argued that this approach not only offers opportunities to better understand the complex relationships between health and place (and other social outcomes) but can strengthen the evidence for causal relationships between the environment and health. Finally, there is a brief discussion of some of our own nascent work considering these issues using longitudinal data collected in the United Kingdom.