Using inheritance, one can extend the base class as per the requirements of the derived class. It provides an easy way to upgrade or enhance specific parts of a product without changing the core attributes. An existing class can act as a base class from which a new class with upgraded features can be derived.

In the example above, you realize at a later point that you have to diversify this banking application by adding another class for MoneyMarketAccount. So, rather than implementing this class from scratch, you can extend it from the existing BankAccount class as a starting point. You can also reuse its attributes that are common with MoneyMarketAccount.