I was working on a Pages document this morning when I decided to save and immediately quit the application.
The moment I did it, I realized I did a mistake: the previous evening I did some edits to the cover of the document, removing the background image, and I forgot to revert.
I tried reopening it and of course cmd-Z didn’t work to revert the change - it could only work before quitting Pages.
Then I thought about using the backup which I usually do.
But then, I also found out a feature which I never used in many years of owning a Mac.
Some applications, including Pages, Numbers, and many other non-Apple apps that use documents, like MindNode, have a
File -> Revert To menu.
You can immediately revert to the latest saved version, but you can click “Browse All Versions…” to enter into the Time Machine view of that file:
From here you can go back to any previous saved version.