In general, buying back expired miles is a good deal. Of course it’s better not to let your miles expire and not have to pay a fee, but mistakes happen. I recently received an email from reader John H. He spoke of buying back miles that had once belonged to him but had expired. Here's an excerpt...

"I call AA to see if I have any expired miles. To my surprise I had 5,723 and then paid $40 to get 5000 back.