1
general::
A person who moves about a great deal and never settles down, as in Kate's lived in ten cities in as many years? she's a real rolling stone. This expression is a shortening of the proverb a rolling stone gathers no moss, first recorded in 1523, which indicates that one who never settles anywhere will not do well. After some 300 years of this interpretation, in the mid-1800s the value of gathering moss (and staying put) began to be questioned, and in current usage the term is most often used without any particular value judgment.
American Heritage Idioms