At one point, I had a decade's worth of SANS course material. So much of it was ancient and no longer valid. I threw it away. It wastes space and could only lea

At one point, I had a decade's worth of SANS course material. So much of it was ancient and no longer valid. I threw it away. It wastes space and could only lead others astray since the industry is always progressing, and Windows NT bugs and hardening guidelines are pretty much meaningless today. Ironically some of the tools SANS taught decades ago are still pertinent today, but courses on them alone... not so much. There are some that I really enjoy and I keep them. But they are very much the minority. Outdated stuff goes to the trash, because when it comes to collectables, most technical books are not and never will be. The ones that are, really are. I still have original QNX manuals because although I'll probably never use a QNX system in a technical manner ever again, there are things in those manuals that are pure gold. Ironically, some of the material is considered modern because of SBCs and whatnot. Like Photon, which under a different umbrella, entails a fairly common feature set these days. So I keep them. A bunch of 15 year old PERL books? Trash. Not the PERL 5 stuff, but that's because I'm not the least bit interested in PERL 6, so there's no update of the bookshelves there. But I definitely haven't kept the pre-Perl 5 books. Why would I? Same with all the old Linux Administrator's Guides et al, because nothing they recommend and focus on even exists in that format anymore.