When I interview that's my first question, because it helps set the stage for being it a dialog instead of a Q&A barrage. It's much easier to also wash people out at this stage (depending on what # you are in the interviewing sequence) when they have strong opinions of on call rotations, remote work, etc. Questions often come to mind as you go along through an interview process and I'd rather you ask up front then have it sit in the back of an interviewee's mind as something they want to remember to ask.