Story-surgery is required at a number of stages - and is more easily done early on in the process. That’s why is worth being brutal with your story or outline before you start writing a script. It’s like baking a cake. Mary Berry says to make sure you measure the ingredients carefully. If you don’t, it’s very hard to remove flour from a cake and add an egg when the cake is in the oven. The script equivalent of removing flour from a cake is through-the-night rewrites, caffeine overdoses, panic, sweat and weight gain. This, in my experience, can be exhilarating, once or twice but is mostly no fun