You will always have to write some code of your own. Even if you use a CodeIgniter, AngularJS, and every prewritten function on StackExchange, still, you will have to write some code to configure the frameworks and to pull it all together.
You will always use some of someone else's code, too. Aren't you using Linux or something? You didn't write your own OS, did you? You're using a database, like MySQL or PostgreSQL or something, right? You didn't write your own database system, did you? And are you using a web server like Apache or Nginx?
So the question is not, should I write my own code or use someone else's. The question is where to draw the line.
I'm a web programmer, your typical LAMP developer (well, LAPP --- I use PostgreSQL). Like many PHP programmers, I first concentrated too much on the PHP. PHP is not the best language, as many have said, but I don't think it's quite as bad as people make it out to be. Anyway, I never took up any of the PHP frameworks. They seemed like too much trouble to adapt. (I should point out that I started with an intranet with a dozen or so applications already built.) I would research PHP frameworks from time to time, but always rejected them all, and felt a little self-doubt in doing so: "Do I suffer from Not-Invented-Here Syndrome?"
But PHP, and scripting languages in general, provide the right level of abstraction, I think. It takes care of memory management. It provides a bunch of functions for HTTP. It has its own templating syntax. It's great if you don't overuse it. In other words, in the MVC pattern, PHP does great for the View and, together with Apache, the Controller. But if you write a lot of your Model in PHP, with all this data processing, checking, calculations, etc. --- well, that's what the database is for, I think.
So, instead of eventually adopting a PHP framework, I learned more and more about Apache and PostgreSQL, and I learned that a lot of the things that I was doing in PHP could be done in SQL or in the Apache configuration, with a lot less typing (a lot more reading but a lot less typing). While most people are busy trying figure out how to write the practically all of the MVC in PHP, I realized that Apache was part of the Controller, PostgreSQL was part of the Model, and the browser was part of the View. I use PHP just to help them out, only when needed.