Many writers have espoused the concept over the years, including possibly the most successful writer, Stephen King. He says in “On Writing,”: Mostly when I think of pacing, I go back to Elmore Leonard, who explained it so perfectly by saying he just left out the boring parts. This suggest cutting to speed the pace, and that’s what most of us end up having to do (kill your darlings, kill your darlings, even when it breaks your egocentric little scribbler’s heart, kill your darlings).... And a little later he says, It’s always easier to kill someone else’s darlings than it is to kill your own.
You know where I'm going with this... I have a writer friend who insists on keeping the same bits of prose in every draft of her novel even though they don't work. But I can only make suggestions, ultimately it's her decision, as it should be.
We all do it. So, if you ever see another writer (like me!) clutching some darlings to their heart, refusing to let go of them: Tell them! And if someone tells you... Listen.