In which cases is it recommended to use interfaces in programming?

Interfaces in programming are used to define a contract that classes must implement without specifying how. It is recommended to use interfaces when:

• You need to ensure different implementations of behavior (polymorphism).
• You want to separate the definition of functionality from its implementation for easier testing and maintenance.
• You plan to use different implementations that can be changed without modifying client code.

For example, in Java, the List interface allows working with different collections (ArrayList, LinkedList) through a common set of methods.