Partnerships are inherently challenging. They require two or more partners to share common goals and to work together over the lifetime of a project. This chapter investigates the durability of partnership arrangements and their adaptability as a key condition for partnership effectiveness and long-term sustainability. It summarizes the responses to this survey and present three case studies examining in greater detail the varying level of adaptability of the three partnerships, the different dynamics of such adaptability and how the partnerships' ability to adapt impacted their effectiveness. The chapter presents a brief history of the Roy Award program and discusses the methodology. It briefly discusses the results of the survey of the 37 partnerships before introducing the three case studies – the Noel Kempff Climate Action Project, Mexico City Metrobús, and Alianza Shire. The chapter provides a comparative discussion of how adaptability influences pathways to effectiveness across the three cases and presents the conclusions.