On one of my very first jobs in around 2000 I got paired with a much more experienced software engineer. He’d been a pro since the early 70s. I was stoked to learn from him.

On like my fourth day he said “now I’m going to teach you the thing that helped me the most in my career…” I waited, ready for the received wisdom. And he said “always number your punch cards so if you drop them they will be easy to put back into order”. I was upset. We were long past the point where punch cards were in use. And then he said “I said what would help _me_ the most, not what would help _you_. Software is always changing”.

I’ve thought about that a lot lately.