How can experienced PHP developers leverage OOP principles and design patterns for better code organization and efficiency?

Experienced PHP developers can leverage OOP principles and design patterns by structuring their code into classes and objects, utilizing inheritance, encapsulation, and polymorphism to improve code organization and efficiency. By following design patterns such as Singleton, Factory, or Observer, developers can create reusable and maintainable code that is easier to understand and modify.

// Example of using Singleton design pattern
class Database {
    private static $instance;

    private function __construct() {
        // Database connection setup
    }

    public static function getInstance() {
        if (self::$instance === null) {
            self::$instance = new self();
        }

        return self::$instance;
    }
}

// Usage
$db = Database::getInstance();