Software Architect's Handbook

Situations where YAGNI doesn't apply

YAGNI applies to presumptive features, as in functionality that is not currently needed. It does not apply to code that would make the software system easier to maintain and modify later. In fact, following YAGNI means you may be changing the system later to add a feature, so the system should be well designed for this purpose. If a software system is not maintainable, making changes later may be difficult.

You may come across times where, in hindsight, a change made sooner would have prevented more expensive changes later. This may be particularly true for software architects if the change is architecture related. Design decisions made for architecture are among the earliest decisions made, and having ...