(petitioners purchased a home in 1974 and claimed to have moved from it, by listing it for sale and moving in with the wife's parents; but, petitioners maintained utility service at old house, often stayed overnight, hosted family events, kept personal belongings in the home, used the Internet at the home (because wife's parents did not have Internet at their home) and maintained mail service; wife renewed driver's license using old home's address and petitioners filed a joint income tax return using listing the old home's address after supposedly moving out; petitioner's sold the home a year after they claimed they had moved out; slightly more than three years after claiming to have moved out, petitioners bought new home and claimed first time homebuyer credit; IRS denied FTHBC on basis that old house was still petitioners' principal residence within three years of purchase of new home; court agreed with IRS based on facts and circumstances test).