We are applying learnings from the SNAPSHOT study to the problem of changing behavior, exploring the design of user-centered tools which can harness the experience of collecting and reflecting on personal data to promote healthy behaviors--including stress management and sleep regularity. We draw on commonly used theories of behavior change as the inspiration for distinct conceptual designs for a behavior-change application based on the SNAPSHOT study. This approach will enable us to compare the types of visualization strategies that are most meaningful and useful for acting on each theory.