In Clojure, when should we use a monad instead of a macro and vice-versa?

There are too many tutorials out there on monads that say... "Look! here is a case where we can use a monad" or "This is what a monad is for". What I want to know is what are some of the steps that people use to come to the conclusion that they can say to themselves - "Gee Whiz! It looks like we can use a monad here!" So when someone tells me... "(blah) has nothing to do with a monad...", it reall