Yes, you know what code you write and you also know how it works. You can find your way around it. But what if you haven't touched a piece of code for months or even years. Or what if someone else needs to work with your code. Prevent a hell: use clearly readable variable names and constants.

He points out an example of what not to do - a specific line from the FUDForum code with multiple variables named with a single letter of the alphabet in a complex if() evaluation. He suggests even using "namespacing" of sorts (PHP6 here we come!) to help compartmentalize your variables to make things even easier.