Big Software Contradiction

One of the famous books in software industry is " The Pragmatic Programmer: From Journeyman to Master ". This book contain set of practical advises how to create better software. For every section I read I have thought about how I'll follow this advise and how it will looks like. When I came to " The Evils of Duplication " section which suggest to follow the DRY (don't repeat yourself) principle (also known as "one point of truth") I thought in order to implement this principle I need to create some functionality only once and then use it whenever this functionality required. It will obviously help to maintain this functionality more easily, in case a problem will be found with the implementation there will be only one place to fix it. The following section in this book was about " Orthogonality " concept. It explained that in many cases fixes in our software code unintendedly change functionality in places we did not want to change. Orth