"Every line of code written comes at a price: maintenance."
A post from 2016 starts there. What follows is eight steps toward code that is easy to delete, and they argue with each other. Step 1: copy-paste code. Step 2: don't.
Both are right. The order is the advice.
Since then, writing got cheap. A screen of code takes seconds now. The price in that first sentence hasn't moved.
Near the end, the post says what extensible code is: "hoping that in three months time, you got everything right." Deletable code works on the opposite assumption.
Code built on a guess ages with the guess.
So does writing.