Non-expiring miles are a relatively recent phenomenon. The original American Advantage program was pretty simple: 50,000 miles got you a free ticket; it was non-transferable; at the end of the year, everything got trashed and you started over again. Needless to say, it was a rather small group that received any benefit at all from the program. Today's many ways to accumulate miles and keep them indefinitely with relatively modest activity is a HUGE improvement; so much so that the term "frequent flyer" is probably a misnomer in the case of many account holders. Frankly, the rules for most programs are so simple and liberal that I can't fault the airlines for not doing any more than they do in those cases where miles actually expire. Why should the airline bend over backwards to give something away or care more about your account than you do yourself? Do you expect anyone else who sells things with rebates to contact you when you fail to make a claim? But I will note that Midwest Express -- an airline whose service is widely recognized as the very best in the business -- sent me a card with a reminder and dollars off certificate in plenty of time to keep the account active if I so desired.