I have never been cruising before, but it seems like I will be spending a lot of time in my swimsuit and no wallet is needed. Is it a good idea/necessity to have a lanyard to carry your room card? I was thinking about purchasing some from the Disney store, 25% off with current promotion, but I do not want to drop $30 on four of them for all of us. If they are a good idea to have, do the kids need one too, or just some for us adults? Or is there something better out there?