We're often told to do them, but what really is their function. I suggest we use the word "roadmap" instead. I do a short demonstration of how I'd create a roadmap before I start to paint so I know my structure, where the emphasis will be and I'll also know if I loosing my way. Because I have a map. Most painters are so excited to start painting, they don't plan out their structure enough. It seems fine at the start but just become more and more apparent they without a map you can get lost in the woods.