My question to you is why are you saving them? Do you plan an F class international trip for a group/family or do you just never find time to use them? I certainly wouldn't be saving them for plans of your retirement if that is in the distant future.
As much as I love watching my point balance climb and get a little sad when I cash out and see the lower balance, any thoughts of lower mileage balances evaporate when I am enjoying a fantastic trip someplace far away knowing that it didnt cost me any more than the tax.
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Addicted to airline miles? Check out:
Mileage Workshop --- "You can't be a real country unless you have a beer and an airline. It helps if you have some kind of a football team, or some nuclear weapons, but at the very least you need a beer." - Frank Zappa (1940-93)