I'm a developer that works alone, and recently, searching for what kinds of documents I still could benefit, even though I don't require anything formal, I've read that one document that still is highly recomended to write is the project vision document.
I found it described as a short document (a page and a half or two) containing what problem has to be solved, how it will be solved and how the end user will benefit from the solution.
Reading more, it seems that this document is one extremely important input to discover the requirements and finaly the user stories.
In that case, considering that this is, as I understood, the first step when starting to build a software, what is the importance of this document, and how is it used so that it helps the development?
I still don't fully get how such a simple and short document can be that important and help that much.
How is this document important and how it is used to help the development process? In particular, what is the role of this document in the requirements gathering process?
Best Answer
Considering you are working alone the vision document would be less useful for you than most as it's mostly a communication tool. More importantly however, the vision document is a reference point, something you can look back to and determine whether or not your efforts are going to the right place.
Even as a solo developer we can be in two minds about design decisions, or change our minds over time. It might be useful to trust your original vision. If your focus for a tool is to be "multi-platform", but you find yourself getting bogged down with using platform specific code because you're rushing solutions, you might look back at the document and remind yourself of your original idea and way of thinking. It can help you prioritise.
The vision document would also help you to communicate with others what it is you are making to fellow enthusiasts, friends and if the project grows in the future to include an audience or other stakeholders.
It forces you to think about all of the right questions: why, how and what. Personally I've found it much easier to recite an "elevator pitch" after writing a vision document, because I just quote lines from the vision document.