I would just like to clarify something. Server 2012 user / device cals are only required for users who store and access resources. Server 2012 user / device cals are not applicable to accounts used for administration or for those that are used for service accounts. Microsoft give you 2 free RDS cals for administration, so why would you be made to buy cals for the accounts used to do the administration.
As per ms best practices, have a day-to-day account and an account for domain administration.