Encumbrance is the balancing factor, and it is quite a subjective one. For the masses, encumbrance means generally not exceeding the space limits of garment pockets, handbag or briefcase or daypack for EDC. Not everyone is subject to that sort of limit for EDC, but it is common enough to use as an example. Now for handbags, briefcases and daypacks, this is in addition to items not intended as essential survival items, although improvisation can capitalize on those items as well in a pinch. This would be items like notebooks, textbooks, cosmetics, office/classroom utensils, etc. So the inclusion of an acoutrement container is still not just for EDC survival purposes. Rather, we are capitalizing on unused space that always seems to be available on such containers regularly.

Most of the time lately I travel pretty light. I don't often bring a shoulder bag or briefcase to work, so EDC is confined to what I can fit in the pockets of my coat, shirt and pants. Naturally I am not going to pack my pockets to bulging capacity as this is neither comfortable nor of much practical use. So for EDC, I am going to narrow my focus considerably and have a list of small very essential items. These should be things I would use often anyways. So EDC is reduced to fundamental lifestyle type necessities, such as a small multitool, a keychain flashlight, a small butane lighter, and so on. My list won't necessarily match what others have, nor be in the same priority, but it is a fair representation I think.

Since it is impractical to carry a BOB or even an expeditionary pack around with you most of the time, it is essential to put less useful but more robust items in it. By less useful, I mean to say things that are less fundamentally necessary for our regular or standard operating procedure. Maybe I should refer to them as limited use items, since that really is their nature. For instance, as an EDC, I might wear my leather coat most of the time, primarily because it is just robust enough to protect me during my daily routine yet I can wear it 9 months out of the year. Conversely, my down parka is only practical under extreme conditions, and so it is of limited, yet vital, use. Limited use items, then augment the EDC and allow us to operate under more extreme conditions, but at the cost of more bulk and weight. Redundancy of some items allows also for upgrading a like item to something more durable, longer lasting, or similarly enhanced. So, while EDC is intended as a compromise between usefulness and bulk, larger packs incorporate both redundancy and enhancement, as well as other non-repetitive items which are also of limited, but vital, use.

There again, even with the larger packs, a balance must be struck between necessity and girth. It is counterproductive to build a kit that is too cumbersome to allow suitable mobility, or one that is not much improved over the standard EDC fare. Therefore, a little planning, some experimenting, and reliable advice will help to determine what sort of items are important enough to include both in EDC and more larger secondary kits.

Ultimately, each person will have to discover that balance for themselves. You study, you practice, you plan, and hopefully you come up with a compromise that satisfies your criteria for what is going to be important and what is more superfluous to have in a situation you might find yourself in.

As I stated at the begining of this post, it becomes quite a subjective thing. I would not expect anyone else to have the same set of EDC items I have just because what I carry is good enough for me. That some might only indicates that we share common lifestyle elements and experiences, but is no indication either of us may have been right in our selection.

In short, there is no universal answer. Sometimes redundancy is essential, other times it is wasteful.