When to use Agile and Non-Agile models ?

Project Attributes	Agile Model	Non-Agile Model
Requirement of the Project	Requirements in Agile model can change as per the customer requirement. Sometimes requirements are not very clear.	In Non-Agile models the requirements are very clear before entering into the development phases. Any change in the requirement is not easily accepted during the development phases.
Size of the Project	The Project size is small in Agile model hence small team is required.	But in Non-Agile models the Project size is usually big hence big team is required.
Design of the Project	In Agile model the architecture is made as per the current requirements.	In Non-Agile models the architecture is made as per the current requirements as well as for future requirements.
Planning and Control of the Project	In Agile model the planning of the project is Internalized and has qualitative control.	But in Non-Agile models the plans are documented properly and have quantitative control.
Type of Customers	Agile methodology is followed by the collaborated, dedicated collated and knowledgeable customers.	In Non-Agile models the customers are of Contract provisions.
Developers required	In Agile model the developers should be knowledgeable, analytically strong, collated and collaborative.	In Non-Agile models the developers should be more Plan Oriented.
Refactoring	In Agile model refactoring is not costly.	But in Non-Agile models the refactoring is very costly.
Risks involved	Usually in Agile models the chances of occurrence of unknown risks are more which can have major impact in the project.	In Non-Agile models the risks are understood clearly and the impact of the risk in the project is very less.