• Disadvantages :
1. Idealized doesn’t match reality well.
2. Doesn’t reflect iterative nature of exploratory development.
3. Unrealistic to expect accurate requirements so early in project.
4. Software is delivered late in project, delays discovery of serious errors.
5. Difficult to integrate risk management.
6. Difficult and expensive to make changes to documents, ”swimming upstream”.
7. Significant administrative overhead, costly for small teams and projects .