What are some common mistakes in PHP session handling that could lead to issues like pages loading from cache after logging out?

When handling PHP sessions, one common mistake that could lead to pages loading from cache after logging out is not properly destroying the session when the user logs out. To solve this issue, make sure to call session_destroy() or unset($_SESSION) when logging out to clear all session data.

// Code snippet to properly destroy session when logging out
session_start();

// Perform logout actions here

// Destroy the session
session_destroy();