The waterfall model is a sequential software development model (a process for the creation of software) in which development is seen as flowing steadily downwards (like a waterfall)

Why different projects require different development methodologies.

I don’t recall when I first saw that term, but I’m sure it was in a pejorative sense. I’m unaware of any article or paper that ever put forth the “waterfall methodology” as a positive or recommended approach to system development.

Many factors can affect the chosen project development method of an organization or project team. When evaluating which approach to take, consider whether the project is familiar territory with a predictable path, or a new frontier with uncertain outcomes

The waterfall methodology forces the solution to be implemented with a design that seemed appropriate at the beginning of the project, but usually ends up being either over or underengineered, resulting in poor performance and excessive maintenance costs.

Applying principles of human visual processing to maximize findability and minimize clutter effects in your windows and web pages.