I'm using this for personal school, and I want to give two dates for a task. One for when I need to start the task and another for when it's due. For example, I have to read a chapter from my textbook by Monday, but it's not just a task for Monday, I need to start it on Friday. A range would be nice because then I could see when I need to start and when it needs to finished. Alternatively, if I could assign that task to be done on Friday and Monday, then I'd know what I need to work on for those days, which could also be useful.