I have a credit on Southwest for $150 that will expire on April 30, 2014. They are not opening the booking window for November until May 19. My trip is planned for Nov. 1-9. Would you book a one-way in late October just to hold (and not lose) the funds and change it when fares open up on May 19? I know it is not worth paying $100 to extend the expiration date. Thanks for your input!