Always keep your surveilance camera damaging laser on you at all times.

A handheld calculator and a slide rule. If the power goes out for a long time, I'll still be doing math while the rest of you chumps will be using your fingers to count to 10.

I can’t be the first person to say this, but a poop-knife.

I keep a bowling ball in my car. It doesn't make sense to have it at home.

I have a roll of dental floss in my hike bag. It's small, super strong, and there's one pile of it in a roll. Could be used for replacement shoelace, laundry line, tying wood together for a shelter, etc.

LEGO brick separator.

Radiator bleed-screw tool on my keyring.

I'm a plumber by training.

I keep a Windows 11 installer USB on my person almost at all times. I've had to perform an impromptu utilman.exe trick (consensually) multiple times. (Replacing the ease of access menu EXE with a command prompt somehow still allows you to get an administrator CMD window on the lock screen, even in 2026).

I have a field transfusion kit as part of my first aid kit in my vehicle, as well as in my bike kit.

So far, it hasn't been useful at all, and hopefully never will be.

Not unusual, but surprising how many times it has come handy in group gatherings.

Flashlights - I am never without one within reach.

A tissue box and hand lotion: because i have serious allergies and always need a tissue and have horribly dry skin that splits open painfully, get your mind out of the gutter

I drive with a collapsible baton in the car, just in case I have to reach something in the backseat.

Paracord. I use it in the house as well as with my SCUBA diving gear. If you need to tie something it's tough stuff, fairly cheap, and can be doubled up to deal with heavier loads. With SCUBA gear you can use it to create tethers for just about anything and if you have one of the camera floats that comes with a cheap little keeper strap save yourself some heartache and replace it with paracord.

An assortment of screws, bolts, nuts, and washers. Always worth having around. Some little thing breaks or you can't find one you dropped maybe the new thing you are putting together was missing one. Bonus tip, buy them at a place that sells by the pound and not the individual item. Atwoods is a place in the US that still does this that I know of but I'm sure there are a few others. Estate sales will also often have a person who will have jars of random stuff for cheap.

A T Wrench set, Standard and Metric. Allen wrenches suck ass, they hurt my fingers and can never get a good turn on the screws. T wrenches give you something you can actually use without hurting your hand.

Furniture slides. They have two types one for use on carpeted floors and one for hardwood floors. It makes moving furniture around so much easier.

I also keep a furniture jack. That makes it easier to lift up the furniture to put the slides in place.

Put a battery operated water alarm in the pan your hot water heater sits in, and change the batteries when you change out your smoke alarm batteries (whenever there is a clock change). TRUST ME DO THIS

I have a dosimeter/geiger counter. So far, it's only been a neat toy for about an hour. I hope it never is more than that.

A small marlin spike. It's surprising how often I want to untie knots in all kinds of things. A marlin spike makes that easy.

Earplugs. They can obviously be used for protection from overly loud environments. They're also great for shutting out voices, music, or other noise when you're trying to read or focus on a task. I like the Loop Switch 2 plugs because they're small, versatile, and effective.

Ultralight folding bag. I carry a 19 liter bag (Nanobag Sling) with shoulder-length handles that folds down to about the size of my thumb. Any time I need to carry more things than will easily fit in my hands, I pull out the bag. It also lets me support awkward or heavy items using my shoulders and back instead of my hands and arms.

Fire extinguisher.

Get a small one and put it in your boot or the back of your ute (seppo: truck).

If you're ever first to a car accident, or have one yourself, you'll be very glad you have it.

Donegan OptiVisor Headband Magnifier - https://doneganoptical.com/product/optivisor/

with optiloupe - https://doneganoptical.com/product/optiloupe/

and Quasar LED lighting attachment. https://www.esslinger.com/led-visor-lighting-system-attachment-for-optivisor-headband-magnifier/

I originally got it when I was doing a bit of electronics work. But every couple of months there'll be times when I really want a hands-free magnified view of something I'm working on, even if it's just for a household chore. There are plenty of cheap knock-off out there, but I believe this is the original. I was at the Intrepid Museum in NYC and there was a photo of a NASA engineer wearing one of these.