The choice you only make once per visit

The shape of a visit

You paste a string, you sign in, you do whatever you came to do, you leave. The address was chosen in the first second and then stopped being a live question.

Nothing in the rest of the visit invites you to reconsider it, and by the time reconsidering would be useful you have accumulated a session, a signed in state and possibly some half finished work.

Why revision is not free later

Moving to a different address mid visit is not the same act as choosing one at the start. It drops the session on the route you were using and starts a new one, with whatever front door checks that involves.

Nothing you have actually saved is lost, because the account and the order record are shared, but anything sitting unsent in a form is on the page rather than in the market. The switching section is entirely about that distinction.

What this means for the choice itself

It means the arbitrariness argued for in there being no correct choice is still correct, but the casualness has a boundary. The decision is cheap to make and moderately annoying to change, which is a different thing from being cheap to change.

That is not a reason to deliberate. It is a reason to make the choice before you start rather than in the middle of doing something, which is also the argument in rotating on purpose.

The one thing worth deciding at the start

Not which address, but whether the three are within reach. If they are in a file you can open, the choice is genuinely revisable at any moment and its cost is a paste. If they are not, the choice you make in the first second is the only one you will get.

A reader who has the set in reach can afford to be careless about which one. A reader who does not is quietly making a decision that lasts as long as their address does.

Why this is not obvious

Ordinary web browsing has no equivalent. A site has one address, you are on it, and there is nothing to reconsider. The idea that your route in is a variable you set once at the start does not exist anywhere else in a reader's experience, so nothing prompts them to think about when they set it.

The practical form

1. Before you paste anything, check the three are somewhere you can reach.
2. Paste any of them without thinking about which.
3. Do not reconsider mid visit unless something has actually stopped working.
4. If you do have to move, finish or abandon whatever is half written first, for the reasons in switching mid message.

A reasonable summary

The choice is trivial and its timing is not. Made at the start, from a set you hold, it costs nothing at all. Made in the middle, from whatever you can find, it is the most expensive decision in this whole subject.

The two questions in the right order

Which address should I use is the question readers ask. Are all three within reach is the question that determines what the first one costs. Asked in that order, the first question becomes trivial and the second becomes the only one worth any attention.

Most writing on this subject answers the first at length and never raises the second. That is backwards, and it is the reason so many readers can recite an argument about which mirror to choose while holding exactly one of them.

What this study is not. It is not a claim that anything is lost from your account by moving between addresses, which is precisely what the equivalence section says does not happen.