Every software developed is different and requires a suitable SDLC approach to be followed based on the internal and external factors. Some situations where the use of Waterfall model is most appropriate are:

1) Requirements are very well documented, clear and fixed.

2) Product definition is stable.

3) Technology is understood and is not dynamic.

4) There are no ambiguous requirements.

5) Ample resources with required expertise are available to support the product.

6) The project is short.