For repeats of the same story, Miss Manners have even suggested "so you keep telling me."
Hmm, wonder if I could use that line on my mum. I adore her, but she has a terrible habit of telling the same story over and over. It's gotten so that I can practically recite the words along with her. And if I try to say "Yes, Mum, I've heard this story before," she gets very offended and says "Oh, SORRY, I didn't mean to BORE you."
The kicker is when she actually comes out with an interesting story that I've never heard. For example, when my daughter was in Paris recently, Mum said nostalgically "Oh, I remember visiting Paris with my friend Brenda when we were in our early twenties, and two gorgeous Dutch boys tried to pick us up." I was all "That's nice ... wait, WHAT?"