Wee Free Men and A Hat Full of Sky
I'm not even sure how many times I've re-read the Tiffany Aching subset of the Discworld series. More than three? It probably depends on whether you count re-reads of just one of the books, or just the whole series.
Obviously I keep coming back to it; it's one of my comfort reads because it's both hilarious and cynical, profound and dramatic, YA and wise. This time through, I re-read WEE FREE MEN, as well as HAT FULL OF SKY, earlier this fall after becoming furious with an encounter with a medical professional who does not read for fun and who treats their patients like the kind of person who doesn't read, i.e. badly.
Pratchett makes me feel sane and healthy, I guess. I'm really glad this series exists.