Norman’s Law of Product Development: A project is behind schedule and over its budget the day it is started.
In his full article, Act First, Do the Research Later, Don Norman emphasizes, among other reasons, that we should be constantly studying and researching our domain, so we can begin designing and building our product as soon as we start. More encouragement from him:
“Stop thinking and start doing,” I admonished them. “Build things. Sketch things. Try out your ideas. Then sit back and analyze. Do, then think.”
Though, has a disclaimer, he also advises: “Any decisions, actions or trial designs in situations of high importance and impact should always be tried out on a small scale first.”