C.Don`t Repeat yourself (DRY)

  1. Summary
    1. Never write even single line of duplicate code , make them a shared code
    2. If you have just two lines of code that is doing almost same job , prefer to refactor them as separate shared function.
  2. Applicability
    1. Throughout the development cycle, particularly during implementation and coding.
  3. References 
    1. http://programmer.97things.oreilly.com/wiki/index.php/Don't_Repeat_Yourself