Miles are worth what you can get for them, not what it cost you to get them. As a rule of thumb, I value them at $.01/mile (down from $.02/mile years ago).

Having said that, I agree with the poster that said it varies, because what you can get for them varies. If it takes more HH points to get a comparable room than it does for Marriott points, than the Marriott points are worth more.

One thing I do when I'm deciding whether to purchase a ticket or redeem miles (assuming it's possible) for an itinerary is divide the price of the former by the # of miles for the latter. These days I'll make the purchase if I'm getting better than $.01/mile. Not a hard and fast rule, but if I'm getting something like .001 per mile, I'd definitely buy the ticket, and if the ratio were $.05/mile, then I'd definitely redeem for an award.

But it all depends. For example, if I need the miles to become elite at year's end, and it's not a big purchase price, I might purchase the ticket. tls