We feel that the only way to develop software reliably, and to make our developments easier to understand and maintain, is to follow what we call the DRY principle: Every piece of knowledge must have a single, unambiguous, authoritative representation within a system. Why do we call it DRY? DRY - Don't Repeat Yourself. The alternative is to have the same thing expressed in two or more places. If you change one, you have to remember to change the others...It isn't a question of whether you'll remember: it's a question of when you will forget.

The Pragmatic Programmer: From Journeyman to Master by Andrew Hunt, David Thomas, Ward Cunningham (Preface)

ISBN: 020161622X This book is available from Amazon