There are many services on the appliance that are turned on by default. Which ones are unnecessary and can be turned off?

We have customized all the operating system settings, so that only the minimum services are running by default on the box. If there is a service that is running, it is because it is needed by the application to operate correctly. You should not alter these services. Some services that are not started may need to be started for some features to work, such as agentless windows collection. But, by default, the operating system on your appliance is configured to provide the most secure, highest performance environment for the application.