I couldn't even begin to imagine how many books I have read, I read them once & don't even keep them, I must move on & learn something new. Your post did make me think what my collection might be worth now or how big my library might be.
I see life as a disposable product & everything within it, One day & at any time it all comes to an end & I was made aware of it at an early age through witnessing loss. I made a promise to myself that day & have remained steadfast & stuck to it.
The only thing I can possibly take from this life to the next is experience & knowledge. Material things in this life will not be making that transition with me so the real value in anything material from this world is the experience & knowledge that I can learn from it.
The materialistic things in life are all just tools to help us achieve enlightenment. I believe we all have different lessons to learn in this life & if your conscience is telling you to go over the same material I would have to say go with your gut feeling & read it again, be that the 12 volumes of the Talmud or Janet & John something is attracting you towards the goal of redoing that task. If you have an itch you have to scratch it or it will drive you nuts.