OO Design

Don't repeat yourself

The Don't Repeat Yourself (DRY) principle states that duplication in logic should be eliminated via abstraction; duplication in process should be eliminated via automation. Duplication is Waste. Adding additional, unnecessary code to a codebase increases the amount of work required to extend and maintain the software in the future.

Rule of Three (code duplication)

is a code refactoring rule of thumb to decide when a replicated piece of code should be replaced by a new procedure. It states that you are allowed to copy and paste the code once, but that when the same code is replicated three times, it should be extracted into a new procedure. The rule was introduced by Martin Fowler in his text "Refactoring" and attributed to Don Roberts.

You aren't gonna need it

YAGNI principle ("You Aren't Gonna Need It") is a practice in software development which states that features should only be added when required. As a part of the extreme programming (XP) philosophy, YAGNI trims away excess and inefficiency in development to facilitate the desired increased frequency of releases. The principle helps developers avoid wasted effort on features that are assumed to be needed at some point. The idea is that this assumption often ends up being incorrect.

Minimum viable product

A minimum viable product, or MVP, is a product with enough features to attract early-adopter customers and validate a product idea early in the product development cycle. In industries such as software, the MVP can help the product team receive user feedback as quickly as possible to iterate and improve the product.