Yagni A Definition by Martin Fowler martinfowler.com Yagni originally is an acronym that stands for "You Aren't Gonna Need It". It is a mantra from Extreme Programming that's often used generally in agile software teams. It's a statement that some capability we presume our software needs in the future should not be built now because "you aren't gonna need it". A late change in requirements is a competitive advantageRequirements proliferation softwareagilefeaturesplanning