I haven't had travel funds expire, yet.
Keep checking for better seats all the way up to an hour before boarding. I was able to get two seats together in row 7 when I was sitting in the airport, waiting for our flight to board. It was at least two hours before boarding time and I decided to check to see if we could get better seats. I was pleasantly surprised to find an aisle and middle seat together in row 7. It turned out that there wasn't a window in that row, which was probably why the seats were open, but it was nice to be at the front of the plane.