The solution is to donate your old books to the library and transition to digital downloads of books. Libraries even take mangas nowadays, and you can go back and visit them if you ever feel the need to reread a series you read 10 years ago. Meanwhile, digital libraries mean I no longer have to fight to keep the piles of books low enough to even see the bookcases. (And my mother and grandmother are/were even worse... My grandmother slept on a cot next to her four-poster bed that was buried in a mound of books, walked down a hallway that was just barely wide enough to pass because stacks of books, and basically would have been a hoarder if it was anything else besides just literal tons of books.)