The build new vs remodel decision is really dependent on the condition of the house you are considering remodeling, especially the foundation, basement, heating/cooling system. Depending on the extent of the remodeling and the length of time you plan on living there, it makes no sense to put a lot of money into an old house with a poor foundation, no drainage, etc.  Building new lets you take advantage of modern methods and technologies but it is going to cost more than just redoing an old kitchen and bath.  Good luck.