What are the potential pitfalls of using frames in PHP for website navigation?

Using frames in PHP for website navigation can lead to several potential pitfalls, such as SEO issues, accessibility problems, and difficulties with bookmarking or sharing specific pages. To avoid these pitfalls, it is recommended to use PHP includes or a templating system instead of frames to achieve a modular and maintainable website structure.

<?php
include('header.php');
include('navigation.php');
// Main content goes here
include('footer.php');
?>