Does every service application have an application pool associated with it?

Question

I was working on writing a script to list the app pool for each service application and I got to the State Service and Usage and Health and Data Collection Service and don't see any app pool property for the object.

Answer 1

There is no App Pool associated with the State Services, because it is just a container(maintains state for user sessions and many out of the box features). What I am thinking, whoever (I mean services application or web application) want to use this state services, use his own app pool & sharepoint services for it.

There is no App Pool associated with the "Usage and health data collection". Again, SharePoint uses timer jobs/ services/ SQL procedures to move the data from logs to database.

also check this: http://blog.tahoepartners.com/index.php/sharepoint-2013-core-service-applications/