Comparison between Various SDLC Models¶

Below is a high-level comparison of several Software Development Life Cycle (SDLC) models.

Aspect	Waterfall	Iterative	Spiral	Agile	V-Models	Incremental
Development Approach	Sequential	Iterative	Iterative	Iterative	Iterative	Iterative
Phases	Linear	Planning, Design, Coding, Testing, Evaluation (Repeated Iteratively)	Planning, Risk Analysis, Engineering, Testing (Cyclical)	Planning, Sprint, Review, Retrospective (Iterative Cycles)	Planning, Design, Implementation, Testing, Deployment (Parallel)	Divided into increments, each with Planning, Implementation, Testing
Flexibility	Low	High	High	High	Moderate	High
Risk Management	Late	Proactive	Continuous	Continuous	Moderate	Proactive
Time-to-Market	Longer	Faster	Variable	Faster	Moderate	Faster
User Involvement	Limited	Continuous	Periodic	Continuous	Periodic	Continuous
Testing	After Implementation	Continuous	Integrated	Continuous	After Implementation	Continuous
Adaptability	Low	High	High	High	Moderate	High
Complexity Management	Linear	Adaptive	Cyclical	Adaptive	Traceability	Adaptive

When to Use Which SDLC Models?¶

Consideration	Waterfall	Iterative	Spiral	Agile	V-Models	Incremental
Project Size	Small-Medium	Medium-Large	Large	Small-Medium	Medium-Large	Small-Large
Project Complexity	Low-Medium	Medium-High	High	Low-High	Medium-High	Medium-High
Requirements Stability	Stable	Evolving	Evolving	Changing	Moderate	Stable-Moderate
Client Involvement	Limited	Continuous	Periodic	High	Periodic	Continuous
Budget Constraints	Fixed	Some Flexibility	Flexible	Variable	Fixed	Some Flexibility
Risk Tolerance	Low	Moderate	High	Moderate	Moderate	Moderate-High
Time-to-Market	Moderate	Faster	Variable	Faster	Moderate	Faster
Documentation Emphasis	Extensive	Moderate	Detailed	Minimal	Moderate	Moderate
Testing Approach	Sequential	Continuous	Continuous	Continuous	After Phases	Continuous
Change Management	Limited	High	Adaptive	Highly Adaptive	Moderate	High

Most Widely Used SDLC Model¶

Agile is the most widely used SDLC model due to its adaptability, customer satisfaction, faster time-to-market, effective risk management, collaborative environment, continuous improvement, iterative development, and sustainable pace.