An automated registration service supported on an application server that interoperates with an IMS (IP Multimedia Subsystem) core network is configured to dynamically register and deregister devices that are all associated with one or more commonly-utilized phone numbers. The service may assign the phone number to registered devices and, in contrast, un-assign the phone number from deregistered devices. The registration and deregistration of the devices may occur based on the amount of interaction with the device and other real-time contextual information. Furthermore, the automated registration service intelligently determines which registered devices to forward incoming video and/or audio calls to based on various contextual information, including the capabilities of device, identified location of a user, user preferences, etc. By intelligently selecting which devices should receive an incoming call, unnecessary use of bandwidth, data, and resources (e.g., battery power) can be reduced.