3 hours. If your Messenger is not in use (no keystrokes or mouse moves) for approximately 3 hours, your account will be put in Away Mode. When you see the orange Away Mode symbol covering your Message area, your Messenger session is effectively disconnected from the server and will not receive any new inbound messages. The green person icon will also be removed next to your name in all of the User drop-down lists for everyone your team. This tells the other users on your team that you are in Away Mode and not available to handle any new texts.

You can also manually put yourself in Away Mode by pressing the orange triangle < A > on the Instant Messenger title bar. It is a good idea to put yourself in Away Mode whenever you are away from your desk and no longer accepting inbound texts. This will instantly update your system-wide 'Logged-In' status, notifying your teammates not to send you any more texts. This feature is also known as User Presence Detection.

If you are in Away Mode for more than 7 hours, your first mouse click anywhere within the Messenger screen will cause a fresh copy of your team's Phonebook to be reloaded from the server.  Your Phonebook data is stored locally to enable faster searches, auto-complete, contact sorting, and so that you can use filters to select contacts quickly for large Group Sends.