A thorough inspection of the property by a licensed home inspector protects you against structural or material problems that are not detectable in a casual walk-through. Home inspections are just as important in new construction as they are in resale. Obviously, buyers can't inspect a home that isn't built yet, but they can request an inspection prior to closing.
In new construction, an inspector will make sure that all mechanical systems are working properly. They may also spot repairs that need to be added to the builder's punch list (a list of items that need to be completed). The buyer, not the seller, is responsible for hiring and paying the inspector.