The fact that such a firm valuation is impossible to arrive at is what keeps the IRS from taxing miles as a form of income. Believe me, they've tried. When you redeem 350,000 miles for a Vizio TV, they're not worth very much. When you redeem 2,000 for a drink at Newark Airport, they're not worth much at all. Redeem 25,000 for a domestic ticket that retails for $300, and they're worth a little more. Redeem the same 25,000 for a last-minute domestic ticket that would otherwise cost you $1,000, and they're worth far more. And if you redeem 100,000 for a first-class overseas ticket that would cost you $7,500 to purchase, they're worth more still.