Waterfall
Waterfall is a linear, sequential software development methodology where progress flows steadily downward through distinct phases: requirements, design, implementation, testing, deployment, and maintenance. Each phase must be completed before the next begins, with minimal overlap or iteration. It emphasizes thorough documentation and upfront planning, making it predictable but inflexible to changes.
Developers should learn Waterfall for projects with well-defined, stable requirements, such as government contracts, safety-critical systems, or large-scale infrastructure where regulatory compliance and documentation are paramount. It's also useful for understanding traditional project management contrasts to agile methodologies, providing historical context in software engineering education and legacy system maintenance.