I tend to save any cable that at some time in my life I needed and had to pay a premium to get. Unfortunately this means I have drawers and boxes full of IDE, floppy, parallel, serial, sata, audio, svideo, vga, dvi, nema15, phone, network, and just about any other type of cable you can think of. I recently had my assistant purge my storage room and I cringed as he threw out boxes full of floppy drives, old monitors, keyboards, mice, and specifically old routers, serial boards, and other stuff that cost tens of thousands of dollars 15 years ago that are worthless today. We depreciate all our equipment fully, so we can't get a tax break for donating it, and even churches and schools no longer take tech that is more than a few years old any more unless fully functioning. Without recycle places nearby, the most cost effective means of disposal is the landfill. Anything of remote value I throw on CL for free and some junky will come pick it up. The stacks of old hard drives pile up until I hit the shooting range for proper decommissioning, but then hit the landfill as well. I saved some copper from solid copper heat sinks once, but after a year I had about $2.50 in recyclable copper, so it wasn't worth it.
To this day, there is a high percentage chance that if I throw something away, I will have a need for it the next day or maybe a week later. BUT, if I save it, I will never find it when I DO need it, at least not until the next day when I am throwing some old stuff out (after I already bought an overly expensive replacement). This can be anything from a screw or nut to a cable to a piece of hardware or even a tool.