The cost of switching, counted honestly

The itemised cost

Pasting a string

Seconds, assuming the set is somewhere you can reach. Considerably more if it is not, which is the real variable.

The entrance

Whatever stands at the front of a route you have not used lately, presented again because it is per route.

Signing in

The same credentials as always, entered again on a route that has not seen you.

Unsubmitted text

Whatever was in a form. This is the only item that can be large and it is entirely determined by timing.

Familiarity

Small and real. A route you use rarely takes slightly longer to navigate because your eye is less used to it.

Four of the five are fixed

Pasting, the entrance, signing in and familiarity cost roughly the same whenever you do it. Together they amount to a minute of mild irritation, which is not a reason to avoid anything.

The fifth item is different in kind. It is zero at the start of a visit and potentially large in the middle of one.

So the cost is a timing question

A switch at the start of a visit costs a minute. A switch mid form costs a minute plus the form. That is the whole of the analysis, and it is why every piece of advice in this section is about when rather than whether.

It is also why rotating on purpose is recommended and casual mid visit switching is not, despite being the same physical act.

The cost of not being able to switch

Worth putting on the other side of the ledger. A reader who cannot switch, because the other two strings are not within reach, faces a search instead. That is the comparison in what a second address buys you, and against it a minute of friction is nothing.

The costs in this study are only worth counting because they are the reason people avoid the move that is almost always correct.

The hidden cost of frequent switching

One that is easy to miss: a reader who moves often never becomes fluent on any one route, and small unfamiliarity makes the adjacent page problem more likely, which feeds the divergence section.

It is a minor effect and it is the only real argument against rotating more often than occasionally.

What the cost is not

• It is not a risk to anything saved. Nothing placed, sent or held is affected.
• It is not a cost paid by the market or by anyone else.
• It is not cumulative. Two switches cost twice one switch, and nothing degrades.

The comparison worth making

A minute of friction against a search conducted under pressure. Framed that way, nobody would ever choose the search, and yet readers choose it regularly because the minute is visible and the search is hypothetical until it happens.

The summary

A switch costs about a minute, plus whatever you had typed. Keep the second term at zero by switching at the start of a visit, and the whole subject reduces to a minute you should be very willing to spend.

The number worth carrying

About a minute, plus whatever you had typed. Not because the minute is precise, but because having a rough figure stops the cost being imagined as larger than it is, which is what makes readers avoid the move.

People overestimate the cost of switching and underestimate the cost of not being able to. Putting a rough size on the first is the cheapest way to correct both at once, and the size is small enough to end the argument.

What this study is not. It is not a measurement, and no figure here is anything more than a description of what a reader has to do.