Advantages:

• Define system requirements before designing internal architecture.

• Design system before writing the code.

• Test system after coding it.

• Easy to track progress.

• Easy to describe.

• Shows basic steps of the design process.

• Easy to define deliverables.

Disadvantages:

• Assumes that all requirements can be known at the outset.

• Not responsive to requirements or design changes.

• Defects found late in the cycle are expensive to correct.

The disadvantages of Waterfall become critical for projects that take longer than about 3 months, or whose requirements are difficult to define. A Waterfall becomes uncontrolled if Feature Creep occurs or if requirements become unstable.