On average, the homes in the East Valley are older than the ones in the West Valley, because this portion of the Phoenix metro was developed first. Many of the cities in the East Valley saw major development begin in the 1970's and 1980's, while the major development in the West Valley didn't start until the 1990's. There are, of course, exceptions, so if you've got your heart set on a newer home, don't ignore the East Valley!