Something I only figured out in the ‘10s is that the main tax of code smells is during debugging. Debugging when taken to the level of art is less about sorting all of the possible causes for a problem by likelihood but by ease of validation.

Things that are cheap to check should be checked first unless they are really unlikely. You change the numbers game from trying to make the biggest cleaving lines possible, to smaller bites that can be done rapidly (and perhaps more importantly, mentally cheaply).

Code smells chum the waters. Because where there is smoke sometimes there is fire, and code smells often hide bugs. You get into Tony Hoare’s Turing award speech; either no bugs are obvious, or there are no obvious bugs.

So I end up making the change easy and then making the easy change because we have more code each week so the existing code needs to be simpler if someone is going to continue to understand the entire thing.

Perl doesn’t seem to have figured this out at all.