What are the main principles you follow when delineating modules in a system?

When delineating modules in a system, I follow these principles:

• Single Responsibility Principle: each module should be responsible for one specific task or functionality.
• Encapsulation: implementation details of the module are hidden, exposing only necessary interfaces.
• Low Coupling: modules should be as independent as possible from each other, so that changes in one have minimal impact on others.
• High Cohesion: all components within a module should be closely related in purpose and work together to perform a common task.
• Reusability: modules are designed so that they can be used in different parts of the application or even in other projects.

For example, in an Android application, modules can be distinguished for network operations, database, UI, and business logic, so that each is independent and easily testable.