What is the difference between Agile and Waterfall methodologies?
Answer
Agile vs. Waterfall represent fundamentally different philosophies: Waterfall is sequential — Requirements → Design → Implementation → Verification → Maintenance. Each phase completes before the next begins. Requirements are defined upfront and locked. Customer sees the product only at the end. Works well for stable, well-understood requirements (construction, manufacturing). Agile is iterative — requirements, design, and testing happen continuously within each iteration. Customer sees working software every Sprint. Requirements evolve based on feedback. The core difference: Waterfall treats requirements change as failure (controlled via change management); Agile treats requirements change as inevitable and desirable. Waterfall excels for fixed-scope, fixed-price contracts with regulatory requirements (medical devices, aerospace). Agile excels for software products with evolving requirements and available customer collaboration. The choice depends on: requirement stability (Waterfall: stable; Agile: evolving), customer availability, delivery timeline preferences, and team culture.