If code is duplicate of some other code maintenance increases 2x. If it's in ten places, it's 10x. If two different version diverge and they should really be th

If code is duplicate of some other code maintenance increases 2x. If it's in ten places, it's 10x. If two different version diverge and they should really be the same (but for some reason one has data packed into an array and the other has multiple arguments, etc.) it becomes impossible to fix it without breaking something