I do a lot of shopping at used book stores for books. I have never minded if they were the *old* ones as they just might have something in them that the new ones don't. Lots cheaper too!!
I generally go to one or two stores. At one,when paying for the books, I find they always add up to as much as I have in my pocket. Sometimes have to run to the ashtray for change. The lady really sees me coming.
My oldest, Mining in the Pacific Northwest, was one I used to get from the library in the 60's. Can't check it out anymore so I bought one on the net. Looked for over 2 years and was rather spendy but I wanted it reeeealy bad. When I got it, it was like new to the point that I don't think it was ever opened. Now my prized possession. Is a 1967 reprint of 1897. Even covers BC mines. Awesome book.
Keep them books. The grandkids may find interest someday and you will have stories to tell.