“Measure Twice, Cut Once” is a reminder that careful planning yields better gratification than going too quickly into operations that can’t be undone. Often, however, it’s better to Measure Once, Cut Twice.
It’s one of the secrets behind how carpenters hang square cabinets in not-so-square kitchens. And it’s one of the secrets behind how developers write applications that are easy to fix when they cause performance problems in production use. The key is to know which details you can plan for directly, and which details you simply can’t know and therefore have to defend yourself against.