Ask

Bone conduction headphones.

I can run and cycle more safely being able to hear my surroundings as well as have some entertainment.

I can wear ear defence whilst working with industrial machines and still listen to music / audiobooks so that time doesn't drag so much. 15 years ago I'd be wearing over ear headphones with everything turned up so loud to try and drown out the machines that it was in no way good for my ears.

I can take acid, go for a walk in nature and soundtrack my trip as well. I love being able to hear the world around me but also mix in music to a good background level so I don't miss out on either audible delights.

I pretty much wear and use them for 8 - 12 hours, 6 days a week, love them!

I'm glad I got myself noise cancelling headphones. Ah, the peaceful isolation from the noisy world.

Noise cancelling in ear headphones. I have had various Sony ones over the years but recently switched to some B&W PI8s as my last Sony ones the batteries had gone. Being able to take my own personal space with me in my pocket is a god send. Sure bigger headphones are better at noise cancelling but they are nowhere near as portable.

Cheapest would be a switch alignment comb for building plateless keyboards. Its basically a big comb that keeps switches aligned, sounds like you do not need one? Try soldering plateless especially if the switches do not have the extra alignment nubs.

Practical is my leatherman crunch. I have had it more than 25 years now and its locking jaws are amazing for its size. Got me out of so many holes with stuck nuts or nuts that need stucking. Bonus points for it supporting hex bits.

Depends on what you consider a gadget.

If you include anything that does small tasks, a multitool is the single best gadget on the planet. I picked up a victorinox multitool years ago. Damn thing is the Cadillac of multitools, but doesn't sacrifice durability to get the comfort and handling. It's a tank with heated leather seats lol.

If electronics are the limitation of gadget, I gotta go with a thermometer. A thermopro probe thermometer means you get perfectly cooked foods, every time. If you get one that's got an alarm on it that you leave in the food, it's even more dummy free.

But even an infrared thermometer helps a buttload in the kitchen. People rarely realize that pan temperature matters as much on the stovetop as it does in the oven, when it comes to reliable, predictable outcomes. That alone will reduce how often you ruin food as you learn how to cook. And once you do, it allows you to dial in exactly the results you want.

a Smartphone

Soundcore p40i earphones. The active noise cancellation is a blessing. Being isolated from noises is a must for me, but they also have a transparent mode that use internal microphones to let the external sounds enter if you need to be aware of your surroundings or are talking to someone.

Miniature handheld paper shredder from Muji

A laser pointer.

A pen

Small gadget? An angled high-CRI pocket flashlight with a magnetic base. I like the Manker E02 series but it's just one option of several.

It's small enough to fit in the tiny pocket on my jeans, gives good light, can be used right from the pocket if I need my hands free, and runs on AAAs (or a 10440 lithium battery for brighter light but worse endurance).

The magnetic base is super useful because I can often just plop the flashlight down while working on something. When I'm upgrading my desktop PC I can just stick the light to some part of the chassis and get light right where I need it.

That's pretty damn good for something that cost me thirty bucks with the 10440 included. And the battery even has a built-in USB-C charging port.

As others have said, it depends where you draw the line on what is a "gadget". But ignoring some of the obvious ones that have already been mentioned several times: I think I might have to go with my desktop audio mixing board. It lets me easily mix sound from multiple computers/devices and run them all into one set of headphones or speakers. I can adjust the volume of each input independently and without futzing with the settings in individual software applications/systems.

My other mention would go to my Raspberry Pi's. Incredibly compact, low-power-usage, but potent, versatile computers. Even just one or two can power a broad suite of at-home/self-hosted services, removing the need for costly, privacy-invasive/insecure, third-party services.

A little wedge-shaped thing that opens jar lids without effort (especially now that I've done weight training and have a grip).