HPSM and Measurements

Hello Experts and HPSM Community,

I'm wondering what other Service Management departments truly use to measure the health and maturity of their service management processes, in the real world.  There are lots of recommendations for possible metrics out there, and I'm sure as an organization refines business processes and fixes bottlenecks the KPIs they are interested in will change. What do you measure in the areas of Change Management, Service Desk Interactions, Incident Management, and Request Fulfillment?