I have thousands of books in my house. I have 6 tall custom-built bookcases in my living room with books mostly in double rows. They're custom so that 12x12 albums fit in the bottom section. I have 3 more custom bookcases in the nook at the end of our dining area - some single rows, some double rows. My cookbooks are on one shelf. In my office there are three tall store-bought bookcases all double rows of paperbacks (horizontal stacking in the back, vertical in the front). I have a small bookrack on my bedroom dresser with my next to read books on it. And I have close to 3000 e-books on my Kindle.
They're organized in a variety of ways. Favorite authors are arranged by writing order of books with any series kept together. I have a section of history books. I have a section of Jane Austen & Austen retellings. I have lots of mystery series - alphabetical by author, in series order for each author. I have a social justice section, childhood favorites (Louisa May Alcott, Anne of Green Gables books).
I read at least 250 books a year. I enjoy re-reading my favorites. I'm lucky enough to be a fast reader.