As discussed earlier, an object has a state, behavior and identity. An object is reusable. Therefore, an object exists as a stand-alone entity that can be used in any relevant context, For example, if you have a chair, you can use the same chair in an office, in a classroom, or in a garden.
An existing object can be used to create a similar object. For example, you have a simple wooden chair and you need to add a headrest to it. You do not need to create a new chair because you can easily add a headrest to the existing chair. This is known as resilience to change.
Realistic Modeling