At this point in time..expiration isnt a significant issue..there are ways to keep your miles 'current' other than flying.. and any time that you add to or use miles it resets the counter on the expiration. you can order something from their shopping network, make donation to charity through their website and many more..depending on the airline. there is a lot of material abt this type of thing and comparisons hidden in the material here on flyer talk. pour yourself a glass of wine and start reading.. it will take a while!!