Applications grow over time. You start with a small piece of software, but along with the business needs the list of functionalities and used tools keeps growing.
At this point, the structure of an application often starts to become confusing and the code more and more monolitic. If this process goes on over the years, you will have then an application that is bridle and slow because of too many bottlenecks.
A common language needs to be shared between developers and product manager. To have that feeling that we are part of a Team sharing a common goal : “how to deliver better and faster business value!”
Agile principles and practices foster that collaboration and common values. They help implementing standardized processes and workflows that work for you in your context, iteratively without revolutionizing your organization.