Inventory

Regardless of what library setting you were working, you will at some point, inevitably, have to check to make sure that what you had the last time you counted, is still what you have today.
This is that dreaded process called:

Inventory

Inventory has several levels.
First you have to determine how much of your collection will get counted at one time. This means choosing between doing a FULL INVENTORY and doing a CYCLE COUNT. Tips for Inventory counts has a lot of helpful suggestions to get you started, but the actual work is up to you.

Second you have to realize that the process of Inventory, no matter which type you choose, will be messy. The tidy books on your shelves will likely need to be moved around. You WILL find books out of place and need to note them for statistics. There is also the possibility that books will have appeared on your shelves that you did not put there. Uncatalogued in your system, refugees from other libraries, subtle donations by your patrons, or perhaps randomly materialized from the ether of L-space, they will need to be dealt with. You will find books that are damaged, books that are faded, books that are on shelves they do not belong on, and books that you thought lost years ago.
Thankfully there are books to help with these issues. Making a Collection Count: A Holistic Approach to Library Collection Management is one, but there are many others.

Third you have to work at it. Inventory counts, full or cycle, don't just happen. They take planning and effort. Sheets, like the one displayed here can be found on sites like Inventory Templates and are a big help in planning and executing a pain-free inventory.

Cheer up!

Inventory isn't the end of the world!

You'll find that once your count is finished you'll be able to handle whatever comes with renewed confidence. And your library will glow with the polish of well loved and happily tidied books, attracting Patron and Management support as never before!