With limited wall space considering how much we have to hang, buying other people's stuff isn't a top priority, but, we do indeed make occasional purchases. I buy work I know I won't make myself...color prints...and enjoy them very much.
What we do to get the most from our wall space is to rotate work. As my wife is an artist, there are new works to hang and older works to retire and/or sell. My own stuff rarely lasts more than two or three months on a wall. The photographs we've purchased, though, stay up for good.