An easy door upgrade for cabinets—that doesn't involve sanding, priming, and painting— does exist. It's all in the knob. A knob in a new color, shape, or texture can change a door's look. Before replacing the old knob or pull, pay attention to the number of drilled holes and the distance between holes. Make sure the replacement fits (or covers up) the existing openings. Otherwise, you’ll have to fill and touch up unwanted holes (it’s particularly difficult to make patches blend in with stained wood). If there’s one hole for a knob, it’s simple to drill another in order to replace the knob with a pull.