Doesn't State of Residency count anymore?

When Bill Clinton was Governor of Arkansas, Hillary was an Arkansas resident; when Bill became President, Hillary was still an Arkansas resident. As soon as Bill got out of office, suddenly Hillary was a New York resident, just because they bought a townhouse in New York. What happened to term of residency prior to running for office? Didn't Hillary think she could be elected from Arkansas? (After the way Bill treated the state, probably not!!)