You aren't gonna need it (YAGNI) Design Principle | Design Principle Tutorial | Design Principle Programmer Guide

You aren't gonna need it (YAGNI) is a principle of extreme programming (XP) that states a programmer should not add functionality until deemed necessary. In other words, Always implement things when you actually need them, never when you just foresee that you need them. YAGNI is a simple principle that asks the programmer to do the simplest thing that could possibly work.