What @standbyyourmantis said about not reshelving is true for public libraries, too. Our funding is dictated largely by how ‘used’ we are, so we scan all the items that are laying about as In House Use. That, tied with Reference Count and Door Counter numbers (we have to manually put in the time we take for references) to prove we’re providing a needed service.
We also have to count the number of people who come for our programs, which not only helps funding but shows that the programming/services are needed, as well.
So, basically, if you want to feel like you’re making sure we’re getting paid and staying around, keep these in mind.