Only Keep the Books You Love
I try to own as few physical things as possible because it allows me to live in a small space and easily move if necessary. I also love to read books, which means I would end up with a lot of them if I didn't buy most in a digital format. To get around the problem of owning too many physical books I follow a decision tree which allows me to figure out what type of book format I should choose. The decision tree favours books in a digital format which keeps to a minimum the total amount of physical books I own.
So, let's say I want to read a book. The first thing I do is find out if the book contains diagrams, which are typically books on visual design. If this isn't the case I get the book in audio format. If I can't find it in audio I buy it in an ebook form. Roughly three quarters of all books I buy are digital - mostly in audio form, and the rest as ebooks.
Alternatively if a book contains diagrams that I have to see I look for the highest quality print version available. I'll take a hardcover over softcover, and the most beautiful and newest edition I can find. If a softcover is all there is then I buy that as they can be very well designed.
If I need to see the diagrams in a book but there isn't an aesthetically pleasing physical version available I get it in a digital format. I'll look for it on Amazon Kindle or a PDF copy if I can find it. These take up no physical space so they don't go against my principle of owning as few physical things as possible.
Once I'm done reading the book if it is hard or softcover I decide if I like it. Would I read it again and again? Is it a timeless classic? If so I hold on to it. Examples: Elements of Colour, Grid Systems in Graphic Design, CODEX: The Journal of Typography. Otherwise I sell it or give it to a friend. If it is in a digital format I archive it regardless if I like it or not.
Applying this system has resulted in me owning only a small amount of beautifully designed physical books. The rest are in an audio or ebook format.