SQL Server - Service User Accounts and Licensing? [closed]

Question

Maybe this is the wrong place to post, since its not necessarily sql server related, but here goes.

If I want to setup some service user accounts in the domain to use to run sql services like the sql server instance itself, sql agent, and others, do I need to be worried about using up user licenses for them?

I believe we are currently using CALs for active directory. I just don't know if this would apply because they aren't real users, just service accounts, but I also don't know if active directory will actually differentiate between the two.

Thanks