Originally Posted by
timmy83
They are 50% off on domestic flights at booking, but free during the check-in period. If you're quick to get in at t-24 you're nearly guaranteed a free EC seat.
If the route is medallion heavy (Gold, Plat, Diamond) you can pretty much forget a free EC seat as a FO.
I would just regularly check the seat map to see if EC seats are getting taken. If yes, pay for one. If not, play the game until check-in.