The spiral cycle of system design is primarily used for high risk projects. All the activities are arranged in a spiral.Each loop represents a development phase and can have any number of loops.
Advantages of Spiral Model
1) Spiral Life Cycle Model is one of the most flexible SDLC models in place. Development phases can be determined by the project manager, according to the complexity of the project.
2) Project monitoring is very easy and effective. Each phase, as well as each loop, requires a review from concerned people. This makes the model more transparent.
3) Risk management is one of the in-built features of the model, which makes it extra attractive compared to other models.
4) Changes can be introduced later in the life cycle as well. And coping with these changes isn’t a very big headache for the project manager.
5) Project estimates in terms of schedule, cost etc become more and more realistic as the project moves forward and loops in spiral get completed.
6) It is suitable for high risk projects, where business needs may be unstable.
7) A highly customized product can be developed using this.
Disadvantages of Spiral Model
1) Cost involved in this model is usually high.
2) It is a complicated approach especially for projects with a clear SRS.
3) Skills required, to evaluate and review project from time to time, need expertise.
4) Rules and protocols should be followed properly to effectively implement this model. Doing so, through-out the span of project is tough.
5) Due to various customizations allowed from the client, using the same prototype in other projects, in future, is difficult.
6) It is not suitable for low risk projects.
7) Meeting budgetary and scheduling requirements is tough if this development process is followed.
8) Amount of documentation required in intermediate stages makes management of project very complex affair.