My use of flags fly in the face of GTD orthodoxy, but it works for me.
I flag items that I want to look at every day, and give due dates to those that require them. All else is unflagged. So that gives me three levels of importance:
TOP: Flagged with due dates - I’ll try to accomplish today everything that’s due today
MIDDLE: Flagged without due dates - I’ll review these daily and accomplish them when convenient
BOTTOM: All else - I look at the unflagged items every week, when I do my weekly review. At that time I’ll flag some items
that feel like they can and should be done this week.
So … each week I see everything in my weekly review. Each morning I look at all the flagged items to see if there’s anything I should change to Due Today. And the rest of the day I just look at Due Today.