If you have dents in the metal-clad doors in your home, one answer is to use auto-body fillers to make the fix. Either the polyester resin or fiberglass paste fillers bond well with steel, and the repair can be made like on a car. But, because you can finish the door with acrylic-latex trim paint, not glossy auto body paint, you don't need the skills of an auto body technician to get excellent results.
Keep waterbeds covered with quilts or blankets to help retain their heat. You might also want to insulate the bottom with a sheet of rigid foam insulation.