I've purchased two small mechanical devices that require the insertion of a battery (not included) to work.
One is a travel alarm, to replace my old faithful which disappeared some time ago, probably left behind in a hotel room. One wants to ensure it works properly. Insert battery, set time, set alarm to go off two minutes in the future, and wait. OK, it works.
The other is a stud-finder. It would be helpful, once I reinstall my hanging shelves, for them not to be knocked down again next time a cat jumps on them. I once had a mechanical (no battery) version of a stud-finder, but I could never figure out how it worked. This one has clear instructions and there's even a demo video on the manufacturer's web site. But that doesn't help. If I am to believe its readings, the studs keep moving around inside my walls. Sometimes they're 20 inches wide. Then they disappear entirely.
Then I've found a box of my mother's old theater programs, mostly 1940s-60s. Most of these can just be dumped: obscure local companies and college productions, touring ensembles. I'm keeping the program from an early touring production of Fiddler on the Roof because it has an article by Sheldon Harnick about how he wrote the lyrics.
And into the box for sale to the used bookstore are a few curious items that, probably, nobody younger than myself will recall from when they were current. Prestige motion pictures, the kind that also had ushers and intermissions, used to come also with program books, as you'd get in the stage theater. But they were large format, at least 11 inches high, and at least partially in color. Souvenir books, really. The expected contents: articles about the movie and its topic, bios of the principal actors and production personnel, stills from the movie and production shots. There were four of these, two of Lawrence Olivier Shakespeare films from the 40s, Henry V and Hamlet, and two from big David Lean films from the 60s, Doctor Zhivago and Lawrence of Arabia.
Those final two were about the last of their kind. I didn't see the movies in the theater, I would probably have been too young not to squirm, but I do remember my parents bringing home the program books and my looking through them. So yeah, I remember these. I wonder if I'll have to explain what they are to the bookstore buyers. I'm sure they've heard of the movies, but the idea of a program book for a movie is so alien now that they may wonder: what are these booklets, what are they for?