People argue about storage as if one answer wins. It does not. Each place trades one kind of loss against another, and the right choice depends on what the loss of that particular item would actually do to you. A passphrase and a delivery window are not the same problem and should not end up in the same drawer by accident.
Four places cover almost everything on this site. A fifth, your memory, is worth naming so it can be ruled out for most uses.
Paper
Paper cannot be read across a network, cannot be copied by anything running on your machine, and does not stop working when a disk dies. It is also the only medium here that a person walking through your room can read at a glance, and it is destroyed by water, fire and tidying.
It suits short things you rarely change and would be badly hurt by losing: recovery material, a seed, a fingerprint you collected. It suits long lists badly, and it suits anything you have to retype often badly, because every retype is a chance to introduce a character that was never there.
An encrypted file
A single encrypted container on a disk you control is the workhorse. It holds long strings without transcription risk, it can be copied to a second disk in seconds, and its contents are only as exposed as the passphrase protecting it.
The failure mode is circular and catches people every year. You put the passphrase that protects the container inside the container. Or you protect it with something you will not remember in six months and have written nowhere else. Whatever unlocks the file has to live outside the file, which usually means on paper.
A password manager
A manager is an encrypted file with better manners. It fills fields for you, which removes the most common way a stored secret gets damaged, and it will keep a history so you can see that an entry changed.
Two cautions. A manager that syncs is putting your material somewhere you do not control, and that is a real decision rather than a detail. And a manager makes it easy to store hundreds of things, which is not the same as knowing what you hold. The inventory on this site is deliberately small enough to hold in your head as a list.
A second machine or a separate disk
Some items exist mainly to survive the loss of the machine that uses them. An offline copy of key material is the clearest case. A copy that lives on the same disk as the original is not a backup, it is the same file twice, and one disk failure takes both.
The cost here is upkeep. A second disk that has not been plugged in for a year may or may not still read, and finding out at the wrong moment is a familiar and miserable experience. Plug it in occasionally with no other purpose than confirming it opens.
Your memory
Memory is unbeatable for exactly one job, which is holding the one secret that unlocks everything else. It is bad at everything else on this list and it fails in a way no other medium does. Paper goes missing and you know it is missing. Memory produces a wrong answer with complete confidence.
So keep one thing in your head, keep it long, and never let it be the only copy of anything that other people also need to be right about. Nothing else on this site should be stored between your ears.
| Place | What it survives | What kills it |
|---|---|---|
| Paper | Disk failure, malware, anything on the network | Anyone in the room, water, a tidy-up |
| Encrypted file | Being copied, casual snooping, a lost laptop | A forgotten passphrase, or storing it inside itself |
| Password manager | Transcription errors, silent edits | Syncing to a place you do not control |
| Second disk | The death of your main machine | Never being plugged in and quietly rotting |
| Memory | Every physical accident on this list | Six months, and any level of stress |
A reasonable arrangement for the material on this site is one encrypted file for the bulk of it, one piece of paper for the two or three things that unlock the rest, one copy of that paper somewhere geographically separate, and nothing at all in a browser or a phone note. That is a judgement, not a rule.
Questions that come up
Is a phone an acceptable place for any of this?
For a delivery window or a rate note, probably yes, since losing either is an inconvenience rather than a disaster. For anything that unlocks money or an account, a phone is a networked computer that lives in your pocket and gets handed to other people, which is a poor fit for material you cannot replace.
How many copies of a thing should exist?
Two, in different places, for anything that cannot be regenerated. One, for anything you can simply fetch again. More than two mostly multiplies the chance that one copy drifts out of step and you cannot tell which one is right.