I see EDC as what I would have on me if I was sitting on the loo at work and the lights went out. Stuff in my jacket pocket or waist pack don't count as they would be left at my desk. Light is my highest priority for EDC; my office lavatories have no external windows, and I don't want to have to decide between waiting for the lights to come back on and wiping myself in the dark. (Was that too much information?)

Although a light and "Rambler" SAK get used several times a week, my EDC also includes a few things for emergencies. Whistle, compass, safety pins, para-chord and fire. (I am very weak on fire - I just don't see it as important in my everyday, urban life). I would use them casually, but in practice I rarely need to. Hopefully they would be useful if I got involved in a 9/11 situation. That's unlikely for my every day life - I work 2 miles from my home, and neither building is a tower block - but I just went to the office party, which was in a posh hotel, and I figured my EDC was all I was willing to carry.

I am coming to believe that with a good EDC I don't really need a PSK in addition. At least if "PSK" means it must be on my person and not in a pack. I have a waist-pack which I usually take if I am straying outside my normal range - I am not sure whether it counts. It mostly contains bulkier and heavier versions of what is already in my EDC. Leatherman Juice instead of SAK, Zipka+ instead of keyring torch, decent compass instead of a button one, etc. It does have a few extras such as a small first aid kit, and sometimes some water. It also has my loose change and an umbrella - if I go out without it I usually end up regretting it.

I am working on a bug-out bag, but it is rather academic here in the UK. We don't have earthquakes or tornados or hurricanes or street riots, and my home is not subject to flooding. I am interested in various kinds of "comfort" kit or camping kits, which are usually based around having the where-withal to prepare a hot drink. A comfort kit is something small enough to carry even if I don't plan to use it, but too big to fit in a pocket. A camping kit is probably what you call a "hiking pack", is bigger and more luxurious - eg a proper mug instead of a tin can. I feel that being able to boil water is important, for comfort, purification and first aid, and that necessarily means a pack which is too big to fit in a pocket. Especially if I am carrying the water too, and the fuel. (Everything around here is owned, and I am not about to set fire to private property.) It takes less room if the bulky items (space bag etc) are stored separately in the pack, so the "kit" concept doesn't really apply.

That's my answer. It was a good question. I try to keep asking myself, what is this kit really for? What scenarios are really likely for me? What would actually help if that happened? What am I taking for granted that wouldn't be true? The answers for the UK are probably very different to the USA.