I'd like to recommend to the group to add your directs to your cell phone contacts.
Measure: In your cell phone (i.e., the mobile number you give to your directs), you have the mobile number and name for each of your direct reports up to date within the past 90 days.
Here is the situation I encountered. In two separate occaisions I've been away from the office, but not someplace where I could hold a phone conversation. I needed to get a quick message to my manager, so I send it in a text message. The first response I got from both managers was "Who is this?"
I don't know if all cell phones do this, but all of the ones I've had do. If I store your mobile number in my contacts list or address book, when you send me a text message, your name shows up with the message.
I had planned poorly in both situations, but I felt like my managers didn't want to help. I felt that they just gave our their mobile numbers because they felt they had to. Neither of these managers were holding regular one-on-ones with me, and I think the relationships developed through those probably would have prevented this situation.
If you find you don't have all of your directs in your cell phone, take one minute out of your next one-on-one to update it. You can say something like, "I'm verifying all of the contact information I have for the team. Is xxx-xxx-xxxx still your mobile number?" and "You know that you can reach me here at the office at xxx-xxx-xxxx or on my mobile at xxx-xxx-xxxx."