How can PHP best practices be applied to optimize the display of navigation elements in a PHP application?

To optimize the display of navigation elements in a PHP application, it is best to separate the navigation logic from the presentation layer. This can be achieved by creating a separate PHP file for the navigation menu and including it in the main template file. By using functions or classes to generate the navigation menu dynamically, it becomes easier to update and maintain the navigation elements across the application.

// navigation.php
function displayNavigation() {
    $navigationItems = array(
        "Home" => "index.php",
        "About" => "about.php",
        "Services" => "services.php",
        "Contact" => "contact.php"
    );

    echo '<ul>';
    foreach ($navigationItems as $label => $url) {
        echo '<li><a href="' . $url . '">' . $label . '</a></li>';
    }
    echo '</ul>';
}
```

In the main template file:

```php
<!DOCTYPE html>
<html>
<head>
    <title>My PHP Application</title>
</head>
<body>
    <header>
        <?php include 'navigation.php'; ?>
    </header>
    <main>
        <!-- Main content of the application -->
    </main>
    <footer>
        <!-- Footer content -->
    </footer>
</body>
</html>