Tracking service utilization

Good morning,

After taking over a group of 100+ RHEL servers, I'm working through the servers from a PCI perspective to make sure there are no unrequired services running. Rather than post about each individual service, is there a way to determine if the specific services are, in fact, needed for the operation of the server?

Some services that are running/enabled on some servers, but not others are things like atd, kudzu, lm_sensors, mdmonitor, etc. Before stopping them and disabling them, I want to make sure that doing so will cause no harm, but I'm unsure how to verify that there are no users/processes that actually use these services.

Anyone got any tips or suggestions as to how I can determine whether or not it is safe to disable services?