RI coverage tracks the number of running instance hours that are covered by RIs, which allows you to understand your RI coverage at a high level (e.g., across all running hours) or dive into detailed information by filtering for a particular set of accounts, instance types, regions, tags, and more. From there, you can use the insights gleaned from this data to optimize your RI purchases for cost efficiency (e.g., by identifying instance hours that are consistently running at on-demand rates and purchase matching RIs).