If I have time I do. I need to answer calls from coworkers, and I don't have all of their numbers programmed into my phone. Some of them don't change numbers when they move here, so I can't go by area codes. So, if I have a moment, I'll answer the phone. If it's a robo call, I hang up (two button pushes). If I sent them to voice mail, at the time I'm ready to listen to voice mail, I have to get to the ap (swipe), open it (push), select the one to listen to (push), oh it's a robo, delete (push). It's actually quicker to answer the phone.
But, if I'm in the middle of something, I don't answer.