Caches and redundancy

The parent page's principle is right and its examples come from a country with a great deal more unowned land than this one. Two is one and one is none holds. The buried pipe does not.

Why the buried cache is the wrong shape here

Almost every square metre of Britain belongs to somebody. Burying a container on land you do not own is unlawful, and the land you do own is the land your house is on, which is the one place a cache is not meant to be.

Beyond the legal problem, buried caches mostly do not get recovered:

• The surroundings change. A hedge is grubbed out, a field is built on, a track is resurfaced, a tree comes down in a storm. The landmarks people navigate to are exactly the things that move.
• People forget. Not the general area, the precise spot. Digging for a buried container in the wrong two square metres, in the rain, is a well-documented experience.
• Access is the problem, not concealment. A cache along an evacuation route assumes you take that route, on foot, with a spade, in circumstances that permit half an hour of digging in a hedgerow.
• Damp wins. British soil is wet. Anything not genuinely sealed with desiccant degrades within a couple of years.

None of that means the parent page is wrong about redundancy. It means the British answer is different, and better, and easier.

The cache that is worth doing

A box at somebody else's house is 95 per cent of the value for 5 per cent of the effort, and it is entirely lawful.

The threat model the parent page names is the right one: fire and flood are the most likely total-loss events, and both are local. A copy of everything that matters, twenty miles away in a spare room, defeats both completely.

Ask before you leave a box with somebody, obviously, and tell them what it is in general terms. Reciprocate by holding theirs. That conversation is the same one the tripwires page asks you to have about somewhere to go, and it can be the same conversation.

What goes in it

Small, boring, and impossible to replace. Not equipment.

• Copies of the documents: identity, deeds or tenancy, insurance policy numbers, birth and marriage certificates, the repeat prescription list.
• The photographs of every room, which is what settles a claim.
• Cash, in small notes.
• A USB stick, with the digital copies, plus a written note of how to open it.
• Printed two-factor recovery codes for email and bank.
• A spare set of keys, house and car.
• A written list of accounts and who to contact, without passwords.
• A change of clothes and a pair of shoes, if the person is happy to store a bag rather than a box. Households that lose a house at 3am leave in what they slept in.
• One thing that matters emotionally. A few photographs that exist nowhere else. This is the item people mourn hardest and it costs nothing to copy.

Not medicines, in somebody else's house, beyond a few days of anything critical, and only with their knowledge.

Where the second and third copies go

The parent page's spatial version of two is one holds, applied sensibly.

• Originals at home, in a fire-resistant box if you have one, ideally low down and in a bag against water.
• Copies off site, per above.
• Digital in two places: the USB in the off-site box, and cloud storage, which is effortless while everything works and useless the moment it does not.
• Paper of the short list in the go-bag, per the documents page.

Vary the failure mode, not just the location. Two USB sticks in two houses both fail to the same thing, which is that flash memory left unpowered for years loses data. Paper plus digital, in two places, covers more than four copies of one format.

Keeping it alive

The reason caches fail is not discovery. It is neglect.

• Refresh it annually, on one of the two fixed dates the skills ladder companion suggests. Numbers change, policies renew, children are born, keys are recut.
• Open the USB stick and read it, on a different machine. A backup nobody has opened is a hypothesis.
• Check the cash is still there and still legal tender.
• Confirm the person still has it, and still has a spare room, and has not moved.
• Write the date on the outside of the box so that anybody looking at it knows how stale it is.

And the parent page's second half, the skills redundancy audit, is genuinely the more important of the two. Two people who can run each critical system is a deeper form of redundancy than any number of boxes, and it is worked through in detail on the knowledge vault companion. A cache replaces objects. Only a second trained person replaces the person.