My wife wants me to get rid of some of my books. It's something she has to say occasionally.
And I always think that there's no way I can get rid of any of my books. They are all essential, and life as we know it would stop without them.
Of course, it's not true. The reality is that we are growing and learning and books that really, really were essential 20 years ago are such no longer. So I'm getting rid of some of them. My rule of thumb is that if I can never see myself reading the book again, there's no reason to keep them.
What I'm troubled thinking about is my Bible concordance. A Bible concordance was an essential for Bible study when I was in college. Mine is keyed to the KJV (one of the reasons I use the KJV almost exclusively is that so many tools are tied into it) and it's an enormous book in which every occurrence of every word (including "a," "the," and "and") in the Bible is provided with the verse references.
But I don't use it anymore. I haven't for years. Because, of course, there are superb concordances online, and in those you can not only search, but refine your search.
And still I hesitate. Because I imagine that some day I might need a book-based concordance. In case of a power outage, for instance.
But on those days when the power is off (I live in North Carolina, and we live with an occasional ice storm with concomitant power line breaks) I'll wait to do my concordance work.
I still don't like reading books on a computer screen, although I think that attitude will seem quaint one day. But study tools such as concordances are made for online work. Getting rid of these books is a good idea.