I have spent most of my testing and debugging time dealing with these same principles over and over.
A brand-new installation of WordPress – with no pages, posts, images, or plugins installed – contains about 450,000 lines of code. WordPress is using this code to build the page that your website visitor requested, and normally it will do it every time they visit, even if that page hasn’t changed. Caching was invented to solve this type of problem.
Pretty much everyone who develops with PHP uses Composer, and if you’ve ever used a PHP framework, you’ve seen the namespaces at the tops of files. I knew how to use these things but I didn’t really understand them until I embarked on a few just-for-learning side projects that I started from scratch.
Creating and implementing a good software application that is both technically and functionally satisfactory is not an easy endeavor. Here are some potential points of frustration, and how each partner can help to smooth the way.