The path toward a renewable energy future relies on the development of materials for electrochemical energy technologies that are not only highly functional but also stable. In this Perspective, we will discuss a framework for the relationships between function and stability, starting by revisiting how we measure stability that should focus on changes to the nature and number of active centers (materials stability) together with monitoring how current/potential change over time during operation (reaction durability). By shifting our focus to materials properties, we then discuss how subtractive and additive processes such as dissolution, deposition, and (de)intercalation contribute to changes in the local surface composition, coordination environment, and phase restructuring that accompany the degradation of electrochemical materials. Ultimately, gaining insights into the processes responsible for changes to active centers during operation will help us better predict and control the durability of materials for clean energy.