The advanced sizing guide should be used instead of the basic sizing guide in the vRealize Operations Manager (vROps) online Sizing tool when additional management packs are going to be implemented. The basic sizing guide provides the default sizing recommendations based on the number of objects and metrics collected from the vSphere environment. However, if the monitored environment includes other types of objects and metrics from different sources, such as management packs, the basic sizing guide may not be accurate. The advanced sizing guide allows the user to specify the number of objects and metrics for each management pack and get a more precise sizing recommendation12. References: 1: vRealize Operations Sizing Guidelines 2: vRealize Operations 8 - VMware Docs