That's a good question. As I buy more and more books, there's hardly any space left at home to store them. Generally, I buy digital versions because they don't take up physical space at home and are more convenient—whether I'm reading on a PC, tablet, or phone. The only exception is if I really, really love a particular manga, or if it's a work by one of my favorite manga artists—in those cases, I'll definitely buy a physical copy to add to my collection. With things I really like, I prefer to be able to hold them in my hands and keep them close by.