Using the advice from this board, I, personally am spending my first miles to upgrade to First coming back to TUS from LGA. This will give me a confirmed First Class Seat (and more importantly a FC ticket) which will allow me to use the FC Check In and hopefully the Elite/FC security line at LGA. On the outward leg, I do not worry about the lines at TUS because in the past they have only taken at the most 45 minutes, but from LGA, based on horror stories on the board, I do not want to spend 2 to 4 hours waiting in lines. So I feel that this is a good use of miles. (plus I still will earn miles on the flight back )