Waterfall Model
The Waterfall Model is a sequential software development methodology where progress flows steadily downward through distinct phases like requirements, design, implementation, testing, and maintenance. Each phase must be completed before the next begins, with minimal overlap or iteration, making it highly structured and document-driven. It originated in manufacturing and construction industries and was adapted for software development in the 1970s.
Developers should use Waterfall for projects with well-defined, stable requirements and low uncertainty, such as government contracts, safety-critical systems, or large-scale infrastructure where regulatory compliance is essential. It is suitable when the project scope is fixed, changes are costly, and thorough documentation is required for audits or handovers. However, it is less flexible for dynamic or innovative projects where requirements may evolve.