Designers who work on an existing product only succeed if they make something that’s truly and clearly better than what came before it. Most people don’t realize how hard that is at first blush. If a product has been around for five years, then that’s five years worth of the blood, sweat, and tears of past designers whose ideas you’re trying to best. Certainly this is possible as nothing is perfect, and our constant culture of learning and improvement means we should expect ourselves to do better year over year, but to think that anyone’s single-night-redesign will work without a hitch is a bit of a stretch.