I find that my availability to answer immediately depends on a number of things, one of which is the urgency or nature of the question. Usefully, in my experie

I find that my availability to answer immediately depends on a number of things, one of which is the urgency or nature of the question. Usefully, in my experience, nobody opens an IM session where they need my help on a production outage with just 'Hi'. :) (I suspect I'm in a minority, but it's also why I hate answering the phone. An incoming phonecall is just a way for another person to unilaterally decide that they need my attention right now, which is often both disruptive and not true).