Benefits of Dependency Injection

This question is often asked at interviews, and a good list of reasons to use it can be found at http://anandmanisankar.com/posts/angularjs-dependency-injection-demystified/:

• Separate the process of creation and consumption of dependencies
• Let the consumer worry only about how to use the dependency, and leave the process of creation of the dependency to somebody else
• Allow concurrent/independent development of the dependency and the dependent entity, while only maintaing a known contract
• Facilitate changing of the dependencies when needed
• Allow injecting mock objects as dependencies for testing, by maintaining the agreed contract