I use most of my miles for vacation first clas travel for both myself and my wife. We've never had a problem, and we do this at least once a year. She's just reached Silver Medallion on Delta in her own right, and we will now start using some of her miles, as well. I've been intrigued by the value computations done by some of you. I've never thought of it that way, but I intend to start counting.