I have never been able to answer this question. I earn all my miles naturally. I couldn't physically do a MR, although I maximize by miles as frequently as possible with Credit Cards and other partners.

I only redeem for intl first vacation flights. My last redemption was 250,000 miles for $23,500 in airfare (2 tix). That's 9.4c per mile. Would I pay $23,500 for a vacation in airfare? No way. When I go to redeem, however, I make sure I get all Flagship and I hit near 10c. That is the only measure I can use -- to me it is "am I getting good bite for my miles?" I figure, I can't be doing this forever, so might as well go places I wouldn't pay for otherwise.

Now if I stopped flying I would probably value them against J. _That_ is what I would pay for. That same ticket would now cost $11,000 for 180,000 miles. That's 6.1c per mile. In this example, I'm not flying anymore so would I go on 180,000 miles in MRs, spend about $4,400 based on what I've seen here, get probably EXP, and save $6.6k ? Based on the Elite + monetary savings, yes, I would.

The answer? More than my fictional 2.5c.