At least that is months. At the shelter I volunteer with we had a St Bernard in there. Pure bred. Beautiful big guy. A woman adopted and him and claimed she had St Bernards before. A week later.....yes A WEEK LATER!!!.....she brought him back because she had to move and couldn't take him with her. She was moving to New York or something. I said the same thing you are saying..."Really? You didn't know a week ago that you were moving??"
Then he got adopted a couple weeks later and the family just loved him. Sent in a story about how the dog and their daughter are best friends. Well, guess what! He was returned a couple weeks later. He kept knocking the little girl down. DUH!! He's a two year old St Bernard!!!
So he is back in the shelter just waiting for that perfect home. It just breaks my heart when they get returned. But at least we know they will find a home and the people don't get the adoption fee returned either.