Hi Tracie, our mountain condo is fairly remote and not everyone gets a good signal up there, depending on their carrier. In fact, we warn them to write down the directions, address, lockbox code before they start their trip in case they don't get a good signal. Because of that, we put in a landline for emergencies. It hasn't quite been a year but so far guests only used it a couple of times to contact us. We have the condo address right next to it in case they have to call 9-1-1 and direct them.
After a year we may reconsider and take it out, but for now we feel better safe than sorry. (I confess that, as a former Girl Scout and Boy Scout leader and first responder, I occasionally go overboard on thinking "safety first.") Guests can call the entire U.S. and Canada but we ask them not to make any other international calls.