Change many pages at once — and keep the change, if it is one you will make again. Most tidying is not one page at a time: a finished project needs twenty pages archived, an import needs filing, a stack of reading needs marking as read. And a few of those changes come round every month, in exactly the same shape. A stamp remembers one so you never have to reconstruct it.
In the Pages palette, turn on Select. Tap pages to add them to the selection — All takes everything currently listed, None clears it. Because All takes what is listed, the palette's own search and filters are how you aim: filter down to what you mean, press All, and the selection is exactly that.
A row of actions appears above the pages as soon as one is selected:
Tag, retype or set a property and a new button appears: ❖ Save as stamp, counting what you have done so far. (Those are the changes a stamp remembers — moving pages, adding them to the table of contents and the rest happen once, to the pages you picked, and are not recorded.) Do two more and it counts three. Name it, and the sequence is kept — in the document, so it travels with it.
From then on, select any pages and choose your stamp from ❖ Stamp…. It presses the same steps onto them in the same order. Each saved stamp shows how many steps it carries, so you can tell Wrap up a project (3) from Mark as read (1) at a glance. Forget a stamp… in the same menu removes one you have finished with.
It tells you what happened: Stamped 14 pages, or Nothing to change — they already match. That second message matters. A stamp that finds everything already in the state it wants has done nothing, and saying nothing at all would read as a failure.
You cannot write a stamp from scratch, and that is deliberate rather than unfinished. A stamp is recorded, never authored. The only things it can contain are things you already did by hand, one at a time, watching them happen — so there is nothing in a stamp that has not already been tested on real pages in front of you. That is what makes it reasonable to press one onto fifty pages at once.
It also means a stamp has no language to learn, no conditions, and no way to express something you could not do yourself. It is a memory of your own actions, not a small program.