Macau, CHINA
Multi-categorization: context grouping
Unlike many of our physical organization systems, todo-lists and action repositories in general are typically lists of words, so they don't have to respect space optimization by characteristics. I mean, you wouldn't store your business shoes in the same place as your business suits, because it is physically inconvenient. But if you had infinite space, that could make a lot of sense. We call that "execution context clustering", which means that you navigate based upon a specific functionality, seeing only what you need. If you were going to play sports, you would see only your sports clothes and shoes. If you were going to hang a paint on the wall, you would see only the exact tools and material you need for that.
Because lists are just lists, you can actually use this approach within your action-repository and that's something more and more applications are providing for the users: independently of where the task comes from (personal, business, ...), you are able to see specific tasks that can be accomplished in the same context. For example, you might be at the supermarket and take the opportunity of buying the light bulb for your reading lamp, as well as paper for your home office, and batteries for your remote. Different purposes served at the same context.
Priorities
On the other hand, the priority of a certain task is critical for its selection, so you also want to explore your action repository based upon priority, which is one the most natural and typical ways to classify items. Beware, though, that priorities are really very dynamic, so keep it simple. I strongly recommend a 'yes' or 'no' system, as opposed to 'abc', or other multi-level priority systems, very hard to keep updating along the way.
An interesting approach might be a time-sensitive approach, which is closer to your guidance: for example, you may have: "to be done this week?" yes or no. Note that I strongly discourage you to assign 'due dates' to your items that are not absolutely mandatory and un-negotiable (like some official tax deadline). If you 'fake' deadlines, you probably won't keep them anyway, and your world will convert those into unfulfillment and guilty feelings. Nothing really good will come from that.
Once again: separate decided to-do's and pools of opportunities
I insist that a fundamental understanding of the system, and particularly of the Action Repository, is the meaning intended in such a collection. You want to list items essentially because they are good opportunities for you to move forward in the direction of desired scenarios. Now, of course some items are almost mandatory (bad things happen if you don't do them), but it seems healthy to understand that most of them aren't.
Imagine you go to New York for a week or so. You have a handbook guide with the best attractions. What would be a good trip to New York: the one where you enjoy yourself most, or the one where you check the biggest number of attractions? Action repositories work just the same way: your mission is NOT to check as many items of as you can. Your mission is to have a good life! (whatever that means to you)
In that sense, I find it very important to separate each folder of you Action Repository, in two lists: things you have decided you want to do during the next time frame, and things you find of potential added value, and rest in your "pool" of opportunities: your 'tourist attraction guide book'. Provided you are happy, you don't necessarily have to run to check them all. In fact, running too much might just be what prevents you from being happy...
To-do-lists need to be prioritized in relevant order according to deadlines and that way they work great as reminders. However you do not want to mix them up with your wishes - they do not belong in to-do-lists.