Problem definition: In many service operations, customers have repeated interactions with service providers. This creates two important questions for service design. First, how important is it to maintain the continuity of service for individuals? Second, because maintaining continuity is costly and, at times, operationally impractical for both the organization (because of potentially lower utilization) and providers (because of high effort required), should certain customer types, such as those with complex needs, be prioritized for continuity? These questions are particularly important in healthcare services where patients with chronic conditions visit primary care offices repeatedly. Therefore, we explore these questions in the context of diabetes, a chronic disease. Academic/practical relevance: Although the operations management (OM) and healthcare literatures suggest that higher continuity is better for health outcomes, the possibility that one could have too much continuity has not been explored. We draw on literature on continuity of care from the healthcare literature and learning effects from the OM literature to theorize and then show a curvilinear relationship. In addition, we further the literature on continuity by examining different categories for prioritization. Methodology: We use a detailed and comprehensive data set from the Veterans Health Administration, the largest integrated healthcare delivery system in the United States, which permits us to control for potential sources of heterogeneity. We analyze over 300,000 patients over an 11-year period who suffer from diabetes, a chronic disease whose successful management requires continuity of care, as well as kidney disease, a major complication of diabetes. We use an empirical approach to quantify the relationship between continuity of care and three important health outcomes: inpatient visits, length of stay, and readmission rate. We conduct extensive robustness checks and sensitivity analyses to validate our findings. Results: We find that continuity of care is related to improvements in all three health outcomes. Moreover, we find that the gains are not linearly improving in continuity, but rather the relationship is curvilinear, whereby outcomes improve and then decline in increasing continuity of care, suggesting that there may be value in having multiple providers. Additionally, we find that continuity of care is even more important for patients suffering from more complex conditions. Managerial implications: Identifying the amount of continuity of care to provide and determining which individuals to prioritize are both of interest to practitioners and policymakers because they can help in designing appropriate policies for staffing and work allocation.