I too followed the carrying a survival tin craze ever since I saw Peter Duncan with Lofty Wiseman on Duncan Dares. It was a very popular idea in Scouts and Venture Scouts (when they existed) from the 80's to 90's and I occasionally used it...
...Once I boiled water in my survival tin...and it was because I needed to! :yikes:
It was after a long climb in Spain, my friend had bought a brew kit, but managed to forget to bring a pot or mug to boil the water in. I was only too happpy to suggest using my survival tin.
It was very arkward and difficult to pick up/use but it did work, and we had a much needed drink. Using the tin like this, was only possible because I habitually carried the tin literally everywhere, I don't carry it in my kit nowerdays, but you know what there have been a few times I've wanted it:
1. A friend asked for something to light candles with at a party (they spent about 20 mins tring to find someone with a lighter).
2. I needed a needle and thread, or sfety pins, when my trousers ripped on an ML course(I used superglue).
3. I used the electric tape from around the tin llid to fix a tent pole. (it worked till I got home).
4. Wanting a candle when my torch batteries died or to melt something like cord(this has happened a many times).
5. The wire saw would have been handy many times over for cutting odds and ends.
6. Brass wire is very handy for fixing things that paracord is to thick or flexible for. (like rucksack external frames, belts, buckles ect)
If I'd have carried it in my pocket every day over the last 20 years everything including the fishing kit would have been used at some point.
It makes me want to put it back in my pocket right now! So why don't I? because the times I've needed it are very far and few between, weeks if not months apart.
As others have mentioned if a situation comes up you tend to "make-do" and cope with what you have at the time. Having a huge collection of kit in pockets or in pouches is fine, I've done this for 20 years, but it's usually when you don't have the stuff that you need it most....hence the "always carried" survival tin.
The danger is you be come reliant on the kits, and if you find you've lost or missplaced the kit, you can loose confidence in a situation and therfore your ability to cope can change for the worse. the answer? sure carry the kit butI'd encourage people to also learn some basics skills like firelighting or making a blade without the kits.
GADGET KEY RINGS:
Specific Key rings with just survival gadgets, all your gadgets on one key ring? I don't like the idea, keys and key rings, as everyone knows are probably one of the top household items to misplace(though you could argue the tin would be equally loosable). also because all the items are free to move and jingle about they will start to scratch and wear against each other, you could find some things are broken or damaged when you need them.
GADGETS ON MY HOUSE KEYS:
A "TRUE UTILITY" survival tool that covers a key, it looks cool, but I've never used it in about 5 years so I'm not sure how useful it really is.
I have the smallest SAK, however I use perhaps once every 2 days if not more,
a "TRUE UTILITY" money safe bout the sise of a peanut, holds tablets, if I need them, I totally reccomend this product!
I also have my keys on a cord and carabina that can be attatched to clothes I'm wearing.
SURVIVAL WALLET CARDS:
I've carried a metal "survival" card tool in my wallet for around 25 years, in all that time I can only recall using it 2 times to tighten a nut on a friends wheelchair, and several times to open a food tin. it takes up a tiny space and it's reletively light so I'll keep in my wallet.
I also have a tiny LED card light, it's cardboard covered in plastic, it's been there several years, and does get used occasionally when I remember it's there. I have no idea how long the batteries last.
THE SURVIVAL NECKLACE:
Well I get the idea but it can't be comfortable, I imagine some days I just wouldn't want to wear it, and that is a major flaw in it's design.
Purely on a fashion point, it dosn't look right with normal clothes, and it would get some very odd looks if your place of work was anywhere near the public sector.
It would only looks right in the wilderness, The most obvious flaw, is to get to one tool you have to take everything apart and potentially loose bits.
SURVIVAL TIN:
If you want to carry anything for "emergencies" I would still reccomend a survival tin, yes they are more bulky, they are heavier, and difficult to pack, but you can carry what you want, it keeps your kit safe/waterproof, and you really can use it as a cooking pot
the best thing about them is you can chuck them in your day to day bag, rucksack or jacket pocket and forget it untill you need it.
If the kits serve to make you more confident that's fine, but make sure you know how to use the various bits, otherwise it's just metal and plastic junk.
The real question is, do you really need any of it?