I don't think you can replaces great themes. But I think people do want to hear fresh arrangements of them. They don't want to hear them played the same way all the time.
“When I first got pregnant, I freaked out. Then I had to remind myself: I'm turning 30.”
“Reminds me of my safari in Africa. Somebody forgot the corkscrew and for several days we had to live on nothing but food and water.”