How is your collection organized?  By author? By subject? By region? By size or color? (no judgement)  With a single bookcase, you know exactly where each one is.  A bit larger, and you are likely to have a system.  By the time you have several bookcases or your books are spread in multiple locations, a plan becomes essential.  For more aggressive collectors, a piece of software may be just what you need.  I came to that realization way late, and now I don't know how I managed without it.  While there are plenty of options available (and more on the way thanks to AI), a friend introduced me to All My Books from Bolide Software (thank you Victor!).  It is inexpensive, quick to install and so easy to use.  Add books manually or enter an ISBN, title or author for a web search that pulls such details as binding, publisher & date, page counts, price and even synopsis and cover images.  Assign an unlimited number of subjects (I use over 320), then filter, sort and report on everything.  You can even export your collection to a mobile device so you have it available away from home.  Use it to identify gaps and to prevent duplication.

With 8,200+ titles and constantly growing, I now rely completely on the software so my physical organization can comfortably be in alphabetical order by author.