The incremental model is a software development approach that divides the project into smaller modules and delivers them in successive stages. It is suitable for projects with clear and well-defined requirements, who face resource or skill constraints, need early and frequent feedback from clients, and have four phases: requirement analysis, design, development, and testing. The model has advantages such as faster delivery, easier testing and debugging, better risk management, and higher customer satisfaction, but it also has disadvantages like the need for a complete and clear definition of the system, difficulty in changing the system architecture, and rigidity of the iteration phases.