David has the advantage because Hillary increases the value
Of their home. Hillary is in essence helping David not only get a sale but a bigger sale. This assistance, unintentional as it is, is not reciprocated. That is a major flaw in the premise of this show. Who wouldn't put their house on the market after the value has been increased and get a newer, better house? Also any family this far in the process of looking for a house has already mentally prepared to move.
share