We recommend using projects for things that can be categorized as "open" or "completed."
We understand projects seems very similar to tasks. From a management perspective, we think projects are much cleaner than using tasks, and can be used like opportunities, but in a different section in our web application, for things that can have two categories, "open" or "completed."
For instance, one of our customers manages apartments for a living, and uses projects to organize apartment cleanings because the cleaning is either "open" or "completed."
Things you can do with Projects:
-Add multiple related files
-Add multiple related opportunities
-Add multiple related people
-Add multiple related companies
-Add multiple related tasks
-Log activities and @ mention your users in them to follow up