Anna Forss has a different take. Check out the link below. She works with the calendars and options.
Please note this is not an argument for or against the Agile methodology versus waterfall. I am just pointing out a couple of useful links. Most of our Microsoft Project clients have been in the construction industry which uses waterfall. On the other hand we see little interest in waterfall from software development, especially web, groups. They much prefer Agile methodologies, with Scrum seeming the most popular. In my opinion the choice of a methodology depends on the project and the domain. There is no one answer as to which is "best".