At my last job I supported a system that was largely built by one person over the preceding 20+ years. This was roughly his philosophy as well. He told me, pa

At my last job I supported a system that was largely built by one person over the preceding 20+ years. This was roughly his philosophy as well. He told me, paraphrased since this was 20 years ago, "Whenever I'm designing a new feature, I always look at what needs to come out at the end, then I can figure out what needs to go in at the start and how it has to flow through." This still sticks with me and serves me well.