Don't repeat yourself (DRY)

The DRY principle is stated as "Every piece of knowledge must have a single, unambiguous, authoritative representation within a system"... When the DRY principle is applied successfully, a modification of any single element of a system does not require a change in other logically unrelated elements. Additionally, elements that are logically related all change predictably and uniformly, and are thus kept in sync. Besides using methods and subroutines in their code, rely on code generators, automatic build systems, and scripting languages to observe the DRY principle across layers. Bron

SOLID

Practisch uitgangspunt voor het schrijven van OO. Dit zijn de vijf belangrijkste OO-principes (bedacht door Robert C. Martin).

Keep it simple, stupid (KISS)

KISS, an acronym for "keep it simple, stupid" or "keep it stupid simple", is a design principle noted by the U.S. Navy in 1960. The KISS principle states that most systems work best if they are kept simple rather than made complicated; therefore, simplicity should be a key goal in design, and unnecessary complexity should be avoided. The phrase has been associated with aircraft engineer Kelly Johnson. The term "KISS principle" was in popular use by 1970. Variations on the phrase include: "Keep it simple, silly", "keep it short and simple", "keep it simple and straightforward", "keep it small and simple", or "keep it stupid simple". Bron

You aren't gonna need it (YAGNI)

"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. XP co-founder Ron Jeffries has written: "Always implement things when you actually need them, never when you just foresee that you need them." Other forms of the phrase include "You aren't going to need it" and "You ain't gonna need it". Bron