Yah, weeding's a necessary evil. But I work for the library of last recourse in my state, and you'd think if anybody was gonna hang onto stuff...!!!
I know one formula weeder who figures it's a shelf sitter if it hasn't gone out in six months! And she wonders why she keeps having to request books from my collection, too.
My collection alas, is self-weeding. I have an 8 percent lost and/or unreturned rate at my branch. And since we don't _do_ inventories at the Boston Public Library, we haven't the foggiest notion what the "walked out the door" rate is. I mark books missing constantly.
*sigh*