"Don't be a slave to history. Don't let existing code dictate future code. All code can be replaced if it is no longer appropriate."By The Pragmatic Programmer: your journey to mastery, 20th Anniversary Edition, 2nd Edition
"Don't rely on the properties of things you can't control."By The Pragmatic Programmer: your journey to mastery, 20th Anniversary Edition, 2nd Edition
"Don't spoil a perfectly good program by overembellishment and overrefinement. Move on, and let your code stand in its own right for a while. It may not be perfect. Don't worry: it could never be perfect."By The Pragmatic Programmer: your journey to mastery, 20th Anniversary Edition, 2nd Edition
"Don't Think Outside the Box—Find the Box"By The Pragmatic Programmer: your journey to mastery, 20th Anniversary Edition, 2nd Edition
"Don’t worry about stating the obvious in a checklist. It’s the obvious stuff that’s usually skipped or missed."By Fundamentals of Software Architecture