Solve every problem once. Two times repeated can be much worse than ten times repeated if one is a dizzying mess (e.g. to handhold some tragic third party API)

Solve every problem once. Two times repeated can be much worse than ten times repeated if one is a dizzying mess (e.g. to handhold some tragic third party API) and the other is a trivial sequence of instructions you'd understand even if dementia forced to read with a finger on the current line. That code wouldn't qualify as a problem so it isn't affected by the rule (but you might still de-duplify if you know that if it changes it should change uniformly)