What are some best practices for extending classes in PHP for object-oriented programming?

When extending classes in PHP for object-oriented programming, it is important to follow best practices to ensure code reusability and maintainability. One key practice is to use the `extends` keyword to inherit properties and methods from a parent class. Additionally, you can override parent class methods in the child class to customize functionality. Finally, make sure to call the parent class constructor using `parent::__construct()` in the child class constructor.

class ParentClass {
    public function __construct() {
        echo "Parent class constructor called";
    }

    public function parentMethod() {
        echo "Parent method called";
    }
}

class ChildClass extends ParentClass {
    public function __construct() {
        parent::__construct();
        echo "Child class constructor called";
    }

    public function childMethod() {
        echo "Child method called";
    }
}

$child = new ChildClass();
$child->parentMethod();
$child->childMethod();