PHP OOP: Why a getter?

Question

I'm a novice with OOP, and I'm having trouble grasping the necessity of a getter method.

In the example:

class foo {
    $this->bar = "test";
}

$foo = new foo();
echo $foo->bar;

What are the potential pitfalls in this situation, assuming I'm using a setter method to properly validate an updated value?

Answer 1

The value of a getter method is that it lets you change your implementation later, but keep the interface the same.