In this chapter, we present a comprehensive overview of how the “renewability/unlinkability” criterion, as defined in ISO/IEC 24745, has been evaluated in the literature. First, we highlight the main difference between the renewability and unlinkability properties: Whereas the former considers different templates in the time dimension (i.e., ability to renew the enrolled template in one specific application at different points in time), the latter focuses on the spatial dimension (i.e., templates enrolled in different applications at the same point in time). We subsequently present a classification of existing evaluation approaches into empirical (qualitative and quantitative) and theoretical methodologies, including representative examples. Then we focus on the main empirical quantitative metrics, as these are the most relevant for general benchmarking of different biometric template protection (BTP) schemes. These metrics are described in a high-level manner, their advantages and disadvantages discussed, and the corresponding links to open-source code repositories included.