The seventy percent statement is an example of a classic waterfall approach. A modern approach is to take agile philosophies and apply them to software developm

The seventy percent statement is an example of a classic waterfall approach. A modern approach is to take agile philosophies and apply them to software development. Waterfall works well when requirements never change and priorities don't shift. Agile works well when you have full control of the requirements and full control of releasing. Your mileage may vary. My 2 cents.