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  • I really hate working on some old code, where some helper methods are spread throughout the whole codebase. Usually I start putting them in some helper classes, but this is so much work. Commented Dec 5, 2011 at 8:34
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    On the other hand, when you try to hard to avoid duplicated code, you might create unwanted dependencies (tight coupling) that hurts maintainability. The big questions is if two parts of code are "accidentally similar" or "similar on purpose". In the first case, it's perfectly ok if one copy is changed and the other one untouched. For example, printing delivery notes and printing invoices might initially be identical, but later, prices are ommited from the delivery notes. In the later case, changing one copy means that all other copies must be changed as well. That's when it becomes an issue. Commented Dec 5, 2011 at 8:51
  • +1 bringing up (bad) memories, but it was the worst maintenance nightmare. Commented Dec 5, 2011 at 10:21
  • The work case of copy and paste I recall had 12 copies of code to handle 6 identified cases. Fortunately, it was a stand-alone module, so it was possible to avoid upgrading it when the rest of the code was upgraded. We couldn't even cleanly parse what it was doing to rewrite it. Commented Dec 5, 2011 at 12:44
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    "logged resulting in yet another fix OF THE SAME THING" - Almost accurate, but you will actually get "Two or more DIFFERENT fixes OF THE SAME THING" Commented Dec 5, 2011 at 13:11