"I suspect most people have their own personal caveat to this essay." I believe anything is OK (even in large numbers) as long as it is easy for one's mind to

"I suspect most people have their own personal caveat to this essay." I believe anything is OK (even in large numbers) as long as it is easy for one's mind to treat it as one "item". Books (and probably your raw materials) are uniform. You put the next one with all the others and forget it, so it creates little additional drag on you. Yeah, up to a point when you need to expand storage, but the general rule remains.