Apologies to those of you that feel Zillow is a great resource to determine real estate values, but it's hard for a website to determine that a particular property's neighbor has a three story baby blue house with yellow trim, or even a prison for that matter. You can update a kitchen or add a bath, but you cannot change your home's location, one of the biggest factors in not only determining what it's worth going in, but what it is worth when you sell it. Normally, there is a discount buying in that house next to the train station the next buyer will expect to have passed on to them when the time comes. Many clients think better of it, no matter how much extra square footage they're going to get. This New York Times article discusses this topic in the extreme.