I used to have a list for my Someday/Maybe tasks, tasks that are not scheduled and are not next actions, but that I'd like to keep around in case, in the future, I decide to promote it to a next action and schedule a due date/time. I also used this list for tasks that recur, but not on a regular schedule. For example, after I complete the "Pick up dry cleaning." task, I move it into the Someday/Maybe list, along with clearing the due date and next action tag. The next time I have taken my pile to the cleaners, I'll move the task back to my Daily list, add a due date, and add the next action tag.

After a while, I realized this could be improved by setting up the Someday/Maybe list as a Smart List. The Smart List is defined by the search

due:never AND NOT tag:na

So, any task that I enter as a Someday/Maybe task would automatically go into this Smart List as long as there is no due date and no next action tag, which is "na" in my system. During my weekly reviews, I scan the Someday/Maybe list, and if there are any tasks that now need to be scheduled and acted upon, I assign a due date and the "na" tag. It will automatically remove itself from the Someday/Maybe Smart List. If I complete a task, but do not want to delete it because I might have to do it again in the future (see the dry cleaning example above), then I clear the due date and "na" tag, and it will appear in the Someday/Maybe Smart List. This method at least saves me time from having to move tasks between lists.

Finally, in my system, Someday/Maybe tasks can be assigned to a project list, and can have other tags and/or location attached for context (e.g. @errands, @phone, @web). These will remain with a task as it is moved in and out of the Someday/Maybe list.