SOFTWARE DESIGN IS KNOWLEDGE BUILDING

Summary from the TLDR newsletter

Software designers usually have a simple concept in mind when writing programs - understanding this concept allows them to find sections of programs that must be altered when an update or correction is needed. Changes made by people who don't understand the original design concept almost always cause the structure of the program to degrade. The changes will be inconsistent or invalidate the original concept. After many such changes, nobody will understand the modified product. Software that has been repeatedly modified in this way becomes very expensive to update.