Before leaving the house in the morning to head to work, you open and close an average of five doors. You begin by opening the bathroom door in order to shower and freshen up. You open the medicine cabinet to get your toothbrush and toothpaste. You reach for your cereal to grab a quick bite to eat and the front door swings shut behind you before you leave. All of these doors and more would not work without a door hinge or two. And how would it feel like without these important door parts? Well picture going into and out of your house through a hole in the roof because you are no strong enough to move a large rock or slab of wood everyday in front of the entrance.