An eye-opening post from programmer Ted Dziuba on “Taco Bell Programming:”
Every item on the menu at Taco Bell is just a different configuration of roughly eight ingredients. With this simple periodic table of meat and produce, the company pulled down $1.9 billion last year.
The more I write code and design systems, the more I understand that many times, you can achieve the desired functionality simply with clever reconfigurations of the basic Unix tool set. After all, functionality is an asset, but code is a liability. This is the opposite of a trend of nonsense called DevOps, where system administrators start writing unit tests and other things to help the developers warm up to them â€” Taco Bell Programming is about developers knowing enough about Ops (and Unix in general) so that they don’t overthink things, and arrive at simple, scalable solutions.
—Ted Dziuba, “Taco Bell Programming“
The same could be said of a WordPress install. Custom functions/plugins are a liability compare to the assets in the core WP functionality.
Getting to know WP core code is well worth the time. I like the PHPXref 0.7: WordPress for its linked cross- references to the definitions and instance of functions, classes, and variable.