If there’s two sources of truth, one is probably wrong. And yes, please repeat yourself.

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4 Software Design Principles I Learned the Hard Way

Like it, super concice and helpful

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<li>Yes, please repeat yourself.</li>
</ol>
Not agree, I mean if you re-use something and you keep your code fragmented in function clear and simple you can make simple utils/tools function.
On a small level you can make reusable things. make some inheritance is always good.
On a workflow/domain level yes you can repeat if its complex.