When use classes or modules in ruby

In Ruby, classes and modules are two different constructs that serve different purposes and have different characteristics.

Classes are used to define and create objects, which represent entities or concepts in your application, such as users, products, or orders. Classes have properties, which are called attributes or instance variables, and they have behavior, which are called methods or functions. Classes can also have inheritance and polymorphism, which means that they can be derived from other classes, and that they can have different implementations or variations.

Modules, on the other hand, are used to define and create collections of related methods, constants, and variables, which can be included or mixed into classes or objects. Modules do not have instances, and they cannot be instantiated or inherited. Modules are used to provide common functionality, such as utility functions, mixins, or namespaces, and they can be used to avoid conflicts or duplication of names or behavior.

In general, you should use classes when you want to define and create objects, and you should use modules when you want to define and create collections of methods, constants, or variables. You can use modules inside classes to provide additional or specialized functionality, or you can use modules outside classes to provide global or generic functionality.