Projects that you dedicate time to every week, in an effort to push them along.
Projects that are likely to take time every week, but you don't dedicate time to them.
Projects that are ongoing, but don't require active attention. You may have tasks on Idle projects, but those tasks dictate when you will work on the project, not the urgency or planned nature of the project itself. Mark any background project as "Idle".
Projects that you have planned for the future. Use the "Start Reminder" field in these projects to notify yourself when it is time to start work on these projects.
Projects that you are interested in working on, but have no planned start date. This is the catch-all for new projects you think of.
These projects are done. They will not appear in most filters and searchable fields. Only mark as "Done" when you no longer need to interact with the project.