Do you prefer your books in physical format or PDFs for reading through the rules? Does it even matter?
As I write this I have 3 books for 3 different systems in easy reach of my desk. In specific Matt Colville's Strongholds & Followers, the GM Screen and Stay on Target for Age of Rebellion, and a L5R 4th ed core book. I also have shelves and shelves stuffed full of RPG books, and cupboards and bins as well.
I have a collection to rival if not dwarf if on my computer in PDF format too. Some of that purposely bought. Others bought through charity bundles via Humble Bundle or a few other programs. Of late I've found myself liking PDF copies more and more if only for the space concerns.
But I always want at least 1 physical copy for the table, just in case.
What about you? Do you have a preference? Do you find it easier to read one kind or the other? Do you like the look of a shelf full of gaming books? Do you prefer the ability for a tiny SD Card of space to hold an entire library?