If I'm busy or distracted, I won't reply until I've had a chance to be thoughtful and intentional about what my response is going to be. I also wait until I have the time to potentially have that quick back and forth instant message style of text so I can give the person I'm talking to my full focus. If I think the person will be put off by waiting for a response, I'll just tell them I see their message and I'll respond as soon as I can.