Please set the standards based on what is required in your organization. Identify the process of Id creation and any cost attached to it. Now define who should have the official email id, based on the cost and the requirement. If there are no cost involved, figure out the do and dont's for the email usage. That should help you determine the allocation better.
Finally for deletion, there can be only one reason and that is end of employment of the employee with the firm. While setting the guidelines, please consider certain technicalities , such as access to the content of the mail box once the employee leaves. There might be few role which will require reference to those communications.
Most of the organizations cover this in their policy for internal usage for IT and infrastructure. Hence look for it accordingly.
31st January 2012 From India, Mumbai
At the joining of an employee, HRD/ Personnel ask the IT department to create office Email for new employee as well as to delete the same when this employee leave the organization (Exit Clearance) or who not going to be exist any more in the Organization.
Second, it is also depends on the HOD/Boss/Supervisors to whom office email should be offer or not according to the nature of work and need of email communication.
Hope im clear to the point and you got the answer
1st February 2012 From India, Gurgaon