1. Triage calls for call back. If they won't leave a VM on my cell it is generally not a serious issue requiring immediate attention
2. To tell people they have reached the wrong number and the person they want to reach is at extension xxx. I use that at a client site because a PM has the same last name as I do since I get calls for him by accident on occasion. This message at least lets callers know they have reached the wrong person so they know to call back and dial the correct extension; which I give in my VM. I do get the occasional idiot who insists they dialed the correct extension, and says so in their VM, and leaves a request for information they need RIGHT NOW. Since I am rarely in my office and all my clients have my cell # anyway those requests generally never get answered. I assume they call back and actually dial the right extension when they do not hear back from the person they thought they left a message.