For those earning miles for upgraded international travel, there is still computed value to taking miles over rebates. I still do it myself, though with much less certainty than a year ago.

The reason for my caution is that given my account balances, the miles I earn over the next 12 months won't be used for 3-4 years, and I have much less faith in reward levels and availability (already the 400 lb gorilla in the corner) staying at today's levels.

I know many will say that the airlines won't impose big increases in miles needed to redeem awards because it would hurt customer loyalty. But in fact Delta, UA and many others have already done so in the last 2 years, and the world didn't end. And who would've thought UA would toss out most of many pilots' pensions? The unthinkable becomes common.

If that AF F reward doubles to 320,000 miles and becomes even harder to book, those rebates plus 3-4 years of interest might look pretty good down the road.