When I put books on hold at the library, I rarely know how “big” the book is (either by external dimensions or the amount of pages). Yes, yes, I know you can actually see the page amount in most library catalog sites. It’s usually there with the printing year and publishing house. But I don’t pay attention to that. It makes things interesting.
Sometimes I am overwhelmed. More than once I have put a book on hold on a whim, only to find myself lugging what felt like a set of Encyclopedia Britannicas home on my next trip to the library.