What I decided (after years of lugging these books around) is that unless I am prepared to make selling them my career or avocation, I have to let someone else do it. Lots of our generation are looking to make a killing. Surely our parents' jewelry, furniture, china, books, silver, whatever has some value, right? It did to them. They counted themselves prosperous because they had it all.
There's a lesson here somewhere, and remind me to find it when I have time. All this stuff has value in the aggregate as holder of myth, image, story. You put all this stuff together in one house, attractively held together by an individual's self-image, and it tells you that person's story. She was cultivated, he was an intellectual, he was this, she was that. Take away the person -- or someone who is willing to act as caretaker to the myth -- and there's no myth. Just stuff. That's why books wind up on ABE for $7.91 (including $3.99 S&H) and dealers in old stuff have rooms full of silver teapots.