Reference
The costs
A pair you cannot resolve still has an answer, which is to behave as though you are on whichever side is cheaper to be wrong about. This page names that side for all of them.
This is the page to use when the test came back ambiguous, or when you cannot run it at all. The column on the right is not a probability. It is what the error does to you, which is a different and much more knowable thing.
| No | Pair | Which way round it hurts |
|---|---|---|
| 01 | Down for now, or finished for good | Calling an outage an ending wastes a day. Calling an ending an outage leaves money sitting inside. |
| 02 | Old address, or one built to be misread | Mistaking a retired address for a lookalike costs a deleted note. The reverse costs your login. |
| 03 | Same page at two addresses, and only one is theirs | Refusing a mirror costs you a tab. Accepting a copy costs your login and whatever you send. |
| 04 | The redirect and the string it stands in for | Trusting a short link as though it were the address is the costly half. The reverse wastes effort. |
| 05 | Your path through Tor, or the far end | Reading a dead circuit as a dead site sends you address shopping. The reverse costs an hour. |
| 06 | Did the set move, or did your copy slip | Blaming your own typing is cheap. Deciding the set moved sends you shopping for a new one. |
| 07 | Loading proves a server answered, and nothing more | Reading a rendered page as an open market is the half that moves money. The reverse costs patience. |
| 08 | Rate limiting against a password that no longer matches | Waiting out a wrong password wastes an evening. Retyping into a counter digs the hole deeper. |
| 09 | When the puzzle is broken and when the reader is | Reading your own misreading as a broken puzzle sends you address hunting. That is the dear way round. |
| 10 | A door you shut yourself against a lock somebody changed | Treating a takeover as a lockout is the expensive way round. The other way costs standing, not money. |
| 11 | Logged out by a clock against logged out by a decision | Shrugging off an ending as a timeout is the costly read. Panicking over a timeout costs an evening. |
| 12 | A code that does not match against a clock that does not | Blaming the code when the clock drifted is the costly read. It ends with people re-enrolling in a hurry. |
| 13 | An absence against a single character out of place | Registering again over a typo is the expensive slip. Hunting a typo that is not there only costs time. |
| 14 | A wait somebody planned against a wait nobody did | Walking out of a queue to go address hunting is the expensive read. Waiting on a jam costs patience. |
| 15 | A deposit that is slow, or a deposit that is gone | Reading a slow deposit as a lost one gets you charged twice. The reverse only costs you time. |
| 16 | The address expired, or it was never issued to you | Writing off an expired address is recoverable. Trusting a stranger address keeps the route open. |
| 17 | A rule about release, or a decision about you | Escrow read as a hold costs one order. A hold read as escrow costs everything you keep adding. |
| 18 | Who took the difference, the operator or the network | A network fee misread is paid once. A market fee misread repeats on every order you place. |
| 19 | A saving on quantity, or a saving on protection | Refusing a real bulk discount costs pennies. Paying outside the flow can cost the whole order. |
| 20 | Money back, or the end of the argument | Refusing a refund is reversible. Accepting a settlement by accident is not. |
| 21 | Still moving, or already refused | A queue misread costs a duplicate fee. A refusal misread costs days of waiting for nothing. |
| 22 | Still settling, or short by a fraction | An unconfirmed payment misread costs a second fee. A short one misread never clears at all. |
| 23 | A date with something behind it, and a date without | Treating an estimate as a window wastes an argument. Treating a window as an estimate loses the boundary. |
| 24 | One request moves a clock, the other moves the money | Granting time you did not owe costs you patience. Releasing money you meant to hold costs you the money. |
| 25 | Asking for a ruling, or handing over information | A needless dispute is tidy. A report filed where a dispute was needed leaves your money undecided. |
| 26 | A word in a database, and an event in a record | Doubting a real dispatch costs a little standing. Trusting a bare flag costs the clock and then the money. |
| 27 | Nothing new to report is not the same as bad news | Calling a stall a loss costs you a weak case. Calling a loss a stall costs you the whole finalise clock. |
| 28 | A rule that runs by itself, and a date somebody prefers | Ignoring a stated preference costs you a cool reply. Ignoring the market's own timer costs you the balance. |
| 29 | Silence and being ignored look identical | Reading real quiet as a snub is cheap. Reading a snub as quiet runs your deadlines down. |
| 30 | Quiet is not the same as gone | Writing off a live seller costs money once. Waiting on an account that is gone costs the time you had. |
| 31 | Feedback tells you a mood, evidence tells you a fact | Overpaying on a flattering score is bounded. Discarding the record that would have settled a dispute is not. |
| 32 | What a signature actually proves | Ignoring a genuine notice wastes an afternoon. Acting on a forged one moves money you will not see again. |
| 33 | The market only speaks in one place | Doubting real support costs you a detour. Believing a fake one costs whatever it asks you for. |
| 34 | An empty history and a claimed history | Doubting a genuine return costs a little patience. Believing a claimed one costs the whole order. |
| 35 | The result is good. Whose key was it? | Doubting a real key costs you a wait. Trusting a stranger key costs you the payment. |
| 36 | The same clean result, months apart | Distrusting a current notice wastes an evening. Acting on a stale one sends money to a dead address. |
| 37 | You cannot check an image, however clear it is | Refusing a real block costs one re-send. Accepting a picture means you verified nothing. |
| 38 | One of these strings was chosen by somebody | Rejecting a real key over a wrong name is a nuisance. Accepting a key on its name is the costly way. |
| 39 | Posted where, and written by whom | Ignoring a real notice wastes a trip. Acting on an unsigned notice about the site is where money goes. |
| 40 | Who granted it, and what were they promising | Treating a real identity as decoration slows a deal. The reverse pays a stranger wearing a label. |
| 41 | Two lists of addresses, two different guarantees | Ignoring a signed list wastes effort. Using a published list on trust is what pays a stranger. |
Why cost beats likelihood
Nobody outside a market can count how often anything happens there. Any figure anybody offers you is either invented or drawn from a sample so small and so self selected that it means nothing. So the honest version of this board never says how common a case is.
Cost is different. It follows from the situation itself. If treating a delay as a loss means sending the money twice, that is a fact about what you would do next, not a guess about anybody else behaviour. It can be stated without inventing anything.
The shape that repeats
Across the board, the expensive direction is nearly always the one where you take an action that cannot be undone. Sending a second payment. Typing a password into something you did not verify. Releasing money you were holding. Deleting a note. Concluding a market has ended and abandoning what is in the account.
The cheap direction is nearly always waiting. Waiting has a real cost and it is not zero, but it is recoverable, and the thing on the other side of the fork usually is not.
So the general rule, when a test will not resolve, is to pick the branch whose action is reversible. That is a poor rule compared to running the test, and it is a very good rule compared to acting on a feeling.
Where this rule does not hold
A handful of pairs have a timer on one side, and there waiting is the irreversible action rather than the safe one. Those pages say so directly, because a general rule that quietly fails on some pages is worse than no rule at all. Check the page rather than trusting the shape.