Kill your darlings, kill your darlings, even when it breaks your egocentric little scribbler's heart, kill your darlings.

For example, the first draft had numbers for a couple of siege engines. But then the manuscript looked to be running long, and I thought "Hang on - a ballista or a cannon will either be something in the background in a wartime siege scene, in which case it's a symbol that stuff just got real and something not to stand in front of, or as a Chekhov's Gun that will show up as a piece of furniture in scene 1 because there'll be a giant monster on the rampage in scene 3, in which case it does Enough Damage To Kill A Giant Monster. So let's not waste that space."

—Phil Masters, discussing writing The Discworld Roleplaying Game