+1. By booking Southwest when you can get the best fares, you lock in that rate with no penalty. If you have to change, you only end up paying what you would have if you waited anyway, and if you don't have to change, you've got yourself a deal. Furthermore, you can change either the outbound or the return without affecting the fare for the other direction. You also avoid checked bag fees on Southwest. Seems like a no-brainer to me.