My wife's family came to Rock Island, Illinois from Belgium just in time to be listed there in the 1880 census. The family is enumerated in that county in every extant federal census taken before their deaths.
For some time I assumed they always lived in Illinois. It turns out they lived on a farm across the river in Scott County, Iowa, for a few years in the 1880s.
Never assume that people didn't move just because they are listed in the same location in two consecutive census records.