Phone is always open for clients.
However just because my phone rings doesn't mean I drop what I may be doing to answer it. I figure if the call is important enough....anyone calling me can leave a quick message..or a good time to call them back at.
In most cases though...I always try to answer the locals I do not recognize to catch them right away...only because they might be wanting to find a dj right away and they want to talk to someone right away.