Maybe I'm overgeneralizing.
Still in my opinion procedural code becomes unmaintainable faster than OO code since you've a more dedicated file structure in OO for your classes which allows to have a better overview of your codebase whereas in procedural you try to group independent functions somehow and when the project gets larger you need a good IDE or search your ass off to find what you search for, or ... just write it again since the function you need differs a little from what already exists, somewhere, maybe.
Also new developers in a project will have a hard time to understand your function grouping into filenames, and you'll have to
remember where what function is to properly include the functions you need, just in case you dont want to include all your code in every file.
