People leave, it’s a fact of life. It just happens. Their desk is cleared, their office re-assigned, they may even be replaced... But what is to be done with their company email account?
Some companies will have an email retention policy, others will deal with the situation when it arises, but one thing for sure, the information will need to be accessed at a future time. This may happen for either unforeseen data requirements, compliance reasons or in response to an eDiscovery request.