As for your bed. My pups sleep with me...and sometimes there are accidents. Someone gets sick and vomits...older pup loses bladder control. My one foster who is incontinent sleeps with a diaper on...and she is also on top of a piddle pad.
My mattress, though, is always protected. I have 2 waterproof pads on it. I learned to do that years ago...learned the hard (and expensive) way. I have a Tempurpedic and do not want to replace it any time soon.