A late change in requirements is a competitive advantage A Quote by Mary Poppendieck The State of Agile Software in 2018YagniComplete and consistent requirementsWelcome changing requirements agilesoftwaredesign
Changing constraints The Constraints Keep Changing The explicit listing of known constraints in the design program helps here. The designer can periodically scan the list, asking, “Can this constraint now be removed because the world has changed? Can it be entirely circumvented by working outside the design space?” Frederick P. Brooks, Jr., What's Wrong With This Model? What's wrong with the rational model constraints