I suppose I effectively have four level of priorities - or, really, four levels of "when I want to see this". They depend on features of OmniFocus:
- On Hold/Someday/Maybe: Items that I don't want to actually delete, but that I also don't want to see right now or at any predictable time in the future. I give these an On Hold status in OmniFocus, so that they don't appear in any of my usual list. I see them when I review and if I specifically set my status choice to Remaining rather than Available. OmniFocus lets me set a review frequency for projects, so if something is really dubious I can give it a monthly, quarterly, even yearly frequency.
- Later: Items that I don't want to see now, but that I'm not comfortable tossing in the Someday slushpile. I give these a future Start Date in OmniFocus, which keeps them out of most lists but ensures that they will pop up even if I don't go look for them. Often, they pop up when their Start Date is reached and I give them another future Start Date because I'm not ready for them.
- Current: Items that I'm likely to actually work on in the near future. When I have too many of these to work, I give them a near-future Start date, so the line between Current and Later is blurry.
- RememberRemember: Items that outrank everything else, that I always want to see - essentially, emergencies. In a perfectly managed life, I would never have any items in this list. I used to implement this with a context because I used a fancy set of Perspectives that I could set to always use that context; I got too lazy to tend those Perspectives so I tend to use a flag.
Since I use OmniFocus, procedures that are influenced by how many times something needs to be copied are no longer relevant - there's no copying and lists can be reshuffled by changing settings. No, this isn't an ad for OmniFocus. But I guess part of my point is that your decisions can in part be based on how quickly certain changes can be made in your system.