Does anyone else here systematically save power adapters from discarded electronic/computer peripherals equipment?
How often do you use them? Right down it looks like I don’t: that power adapters don’t seem to break down.
Only if they’re a “standard” output voltage like 5 volts or 12 volts DC where i might actually be able to repurpose them.
I keep anything with a USB charging capability because they’re really, really useful.
When I worked in electronics retail we used to salvage the AC adaptors from returned but written-off stock; we kept them in a big box out the back and if a customer came in, was buying something else (or needed a replacement for a faulty product they’d got from us) and wasn’t a complete dickhead and needed one, we might give it to them free from The Box.
The contents of The Box varied from store to store but typically included all manner of AC adaptors, USB cables, Ethernet Cables, 3.5mm Aux leads and power cables. Didn’t matter which company I was working for, there was always a The Box somewhere, and knowing exactly what was in The Box was the sole province of the folks in the tech department. 
I re-use adapters. In fact, I used to buy them from thrift stores for a buck for various projects.
But I’ve cut waaay back on my electronics repair/restore hobby so not so much anymore.
Yes, particularly 12v DC for some LED bars I use as aquarium lights.
I built a couple Arduino and Nixie clock projects where an old power adapter worked just fine for $5 from Goodwill. Just check the voltages and plug size/polarity first.
I’m a EE, so I naturally save these.
The 12V and 5V ones are particularly useful, but other ones occasionally come in handy.
I have a big box of them that I dig through to find one that will work when I have a project.
Not a huge box, but yeah, I got a lot of 'em. Cables, too.
I’ve reused a few. Made an LED nightlight using one. Used another to replace batteries on some motion-activated lighting, and yet another to replace the batteries in a clock.
And Amperage (or Watts).
Good lord, we have a whole drawer full of them, and just recently for the FIRST TIME EVER, I dug through it to find one that worked for a visiting friend’s camera. It felt very exciting … but also reminded me I should throw them out, because it’s an entire drawer and it’s proven useful one time.