g01d4 writes "I volunteer at a used bookstore that supports the local library. One of my tasks is to sort book donations. For > 5-year-old computer books the choices typically are to save it for sale (fifty cents soft cover, one dollar hardback), pack it, e.g. for another library's bookstore, put it on the free cart, or toss it in the recycle bin. I occasionally dumpster dive the recycle bin to 'rescue' books that I don't think should be pulped. Recently I found a copy of PostgresSQL Essential Reference (2002) and Programming Perl (1996). Would you have left them to RIP? Obviously we have very limited space, 20 shelf feet (storage + sale) for STEM. What criteria would you use when sorting these types of books?"