Purpose of Roles

To use roles effectively, consider these types of questions about user needs and administrator responsibilities:

Which departments and organizations have users to be managed?
What additional accounts in managed endpoints will users need?
Which users should be administrators of other users?
Who should manage the administrators?
What admin and access tasks are needed in each role?
Who should create roles and tasks?
How can I use roles to delegate work?
The last question concerns sharing the work of managing users and granting application access. More information about the delegation model exists in Delegated Administration.

Based on your answers to these questions, you can decide how many and what kind of roles are needed.