You are forgetting to measure. You are saying something to the effect of "if I fry potatoes for too long, I get coal, therefore it's best to eat potatoes raw".

You are forgetting to measure. You are saying something to the effect of "if I fry potatoes for too long, I get coal, therefore it's best to eat potatoes raw". How much to invest in design vs how fast can things be done w/o such an investment is a difficult problem. Very similar in nature to https://en.wikipedia.org/wiki/Multi-armed_bandit https://en.wikipedia.org/wiki/Multi-armed_bandit . Sometimes the program you are writing is so worthless, it'll be thrown out tomorrow. Sometimes it may outlive you. The later is rare, but not impossible. Eg. my former boss has some of its code flying on an satellite, circling the Earth some 30 odd years. My personal oldest code that is still alive (that I'm aware of) is some minor stuff in cl-gd library (Common Lisp bindings to GD library). It's about 15 years old now. For my day job, I work for a company whose codebase was started some time in late 90's. While things have changed over time, some, and especially design decisions are still there. A lot of them are painfully wrong, and have been a burden on this company for the last 20+ years. Oh, and should I mention the 32-bit sized IPv4 addresses? ---- How much should one invest into design? how often should cornerstone ideas be revisited? -- Definitely not nothing and definitely not never. But how to know when it's the right amount? -- I don't believe anyone has a strategy for finding out. Good (or lucky) project managers will have a good guess about the timing.