Think about baking a cake. You mix the ingredients, put it in the oven, take it out and serve it. The process has a fairly clear endpoint. Now think about growing a garden. You plant the seeds. You water them. You observe what grows. You prune, nurture, adapt and respond to the seasons. You never really finish caring for a garden. Great design is much closer to gardening than baking. A product, service or business strategy needs attention long after its launch. People change.