I need an iPhone compatible smart watch. All it has to do is reliably notify me of calls and messages and ideally answer calls. I don't need any other function, so anything more is a bonus. It's mainly for use in the house so I can leave my phone in one room and be in another without missing a call. I think most smart watches can function at any distance from the phone as long as they're both on wifi, is that right? Very happy to buy refurbished. Thanks!