What is the best practice for maintaining data across PHP script executions?

When maintaining data across PHP script executions, the best practice is to use sessions. Sessions allow you to store data that can be accessed across multiple pages or script executions for a specific user. By using sessions, you can store and retrieve data easily without having to pass it through URLs or forms.

// Start the session
session_start();

// Store data in the session
$_SESSION['username'] = 'john_doe';

// Retrieve data from the session
$username = $_SESSION['username'];

// Destroy the session when no longer needed
session_destroy();