At our old house, we lived on a city lot and the back yard had a fence around it. If we were working in the front yard, the dog was usually by our side, but didn't wander off.
Since we moved to the new house last April, we never got around to putting a fence up for the dog. She has full run of our 3.6 acres, and amazingly enough, she knows where her boundaries are! /forums/images/graemlins/shocked.gif We've been lucky that she hasn't chased a squirrel into the neighbor's yard or into the road! She slithered under the next door neighbor's horse fence once not long after we moved in, but now she just runs alongside the fence, chasing the horses up and down the fence line.
We let her outside, and she just sits out there forever watching the world go by! /forums/images/graemlins/grin.gif