I find it very hard to work if people are calling me. I have to be focussed on what I am doing. It makes things go a lot smoother and faster! If I get a call and then go back to coding I have no idea what I was doing and where I am at. I will have to spend a couple minutes thinking about what I need to do next and then get back into it. It is a big waste of time and can be discouraging! So you might as well just turn them off and get some work done. Just leave a custom message on your phone or something!