The number of process workflows in your environment corresponds to the number of project workflows that you require. Many projects can use the basic three-task model of the Standard workflow. While this model might suit one group of projects, other projects might require a different set of approval tasks.
For example, your site might support various languages. Therefore, all content must be translated into several languages, and each translation requires its own approval task. In this case you need several project workflows, one for each set of tasks, and a unique process workflow for each project workflow.
