The advantage of spiral lifecycle model is that it allows for elements of the product to be added in when they become available or known. This assures that there is no conflict with previous requirements and design.
This method is consistent with approaches that have multiple software builds and releases and allows for making an orderly transition to a maintenance activity. Another positive aspect is that the spiral model forces early user involvement in the system development effort.
On the other side, it takes very strict management to complete such products and there is a risk of running the spiral in indefinite loop. So the discipline of change and the extent of taking change requests is very important to develop and deploy the product successfully.
The following table lists out the pros and cons of Spiral SDLC Model:
Defining increments may require definition of the complete system.
Not suitable for smaller projects.
Management complexity is more.
End of project may not be known which is a risk.
Highly skilled resources are required for risk analysis.
Project.s progress is highly dependent upon the risk analysis phase.
Easier to manage risk - High risk part is done first.
With every increment operational product is delivered.
Issues, challenges & risks identified from each increment can be utilized/applied to the next increment.
Risk analysis is better.
It supports changing requirements.
Initial Operating time is less.
Better suited for large and mission-critical projects.
During life cycle software is produced early which facilitates customer evaluation and feedback.