Understanding the Two is One, One is None Concept

You’ve probably heard preppers say it a hundred times: “Two is one, one is none.” I’ve had Marines, Navy SEALs, and Army Rangers each swear up and down that the phrase came from their branch, so the true origin is anyone’s guess at this point. What matters more than where it came from is what it actually means, and once you really understand it, you’ll start seeing the gaps not only in your preparedness but in everyday tasks as well.

Whether you apply it to something like a bug out bag, your vehicle emergency kit, or the kitchen tools you use most, it’s a helpful and important principle.

The Basic Idea of Two is One, and One is None

The idea behind two is one, one is none is simple: have more than one way to get something done. If a piece of gear breaks, gets lost, or gets loaned out and never comes back, you’ve still got something that works. A backup. Being prepared means assuming something will go wrong eventually, not hoping it won’t. A backup isn’t overkill. It’s just common sense with a little insurance built in.

Example 1

For example, in your bug-out bag, you should have a few different ways to get a fire going. If all you have is a single butane lighter, what will you do if it runs out of fuel? Or gets lost? Or breaks?

When possible, have three methods or pieces of gear to accomplish basic tasks. For example, in my fire kit, I have the following:

• Butane lighters (2)
• Ferro rod with striker
• Strike anywhere matches

Example 2

I also have several different types of ready-to-light tinder:

• Cotton cosmetic rounds coated in paraffin (simple to DIY)
• Wet Fire cubes
• Tinder tabs

Example 3

A sharp blade is one of the most important survival tools. That being the case, it makes sense to have two or three different types to keep in the car, my purse, an emergency kit, in a first aid kit, and so on.

• A sheath knife. Gerber is a reliable knife brand for this.
• A folding knife. This doesn’t have to be expensive or fancy. Something strong, basic, and small enough for a pocket or purse/backpack pouch will do the job.
• A small multi-tool, such as the Gerber Dime, which I truly love. Pick the size of multi-tool that works best for you. Maybe a larger and heavier one for the vehicle or bug out bag, and a mini for your purse.

The Multi-purpose Nature of Two is One, One is None

This whole idea behind having a backup or two for essential gear is one reason why multi-purpose items are a great idea. Rather than bog down your pack with a ton of stuff, you can cut down on weight while still achieving your goal of having multiple backups.

To accomplish this, take a good, hard look at your survival kit or bug-out bag. In an outdoor setting, do you have multiple ways to:

1. Start a fire?
2. Light up the night with a high-lumen LED flashlight?
3. Cut cordage, firewood, and other things?
4. Signal for help?
5. Navigate your way to safety?

For anything you don’t have at least three methods of accomplishing, take the time to figure out and add another one or two. Some may be multipurpose, such as a flashlight. That can help to light up the night and signal for help.

The Pro and Con of Multi-purpose Items

The upside of multi-purpose items is that you need to pack less overall in your bag, which means it weighs less.

The downside is that if it is broken or lost, you are now down by one item in at least two categories.

It’s your responsibility to weigh the cost/benefit of using a multi-purpose item. Just be sure to consider it rather than be caught off-guard in an emergency situation with two or more capabilities unavailable, not just one.

Applying Redundancy Beyond Bug-out Bags

This idea of redundancy and backups must also extend to your other preparedness areas.

What About Modern Conveniences?

Are many of the conveniences you rely on are powered by electricity? How will you accomplish these tasks if there isn’t electricity? Here are a few scenarios:

• You store wheat berries and grind them into flour using an electric grain mill. Do you have a manual method that doesn’t involve mill stones?
• All of your emergency lighting relies on batteries. What if life gets busy and those batteries you meant to buy at the store…are still at the store when the power goes out? Could you make a light source?
• Your camping stove is your off-grid cooking method...and then you discover the valve is damaged and won’t couple with the propane tank. How will you cook or even heat water?

It’s important to consider these types of possibilities for things that are critical to survival and plan for backups.

What About Skills?

We’ve spent most of this article applying the concept of two is one, one is none to gear and supplies. Yet, it is just as important to talk about redundant skills.

Using the example above of fire kit redundancies, one must also know who to use each of these methods. If I include a ferro rod and striker but don’t know how to use them, I may be in a world of hurt when I NEED a fire to survive. Have I built fires before? Can I build them in windy conditions? Wet? Have I built them from just what is available in my environment, not using pre-made tinder and accelerants? Because what if I didn’t have those?

You see what I’m getting at? Just as it’s important to have multiple pieces of fire-starting gear, it’s equally important to have practiced the skills to use each of them.

Paperwork

The same goes for important paperwork. Your grab-and-go binder can exist in physical form and can be stored in the Cloud. Ditto for your family emergency communication plan. You should have the information in your phone and also in hard copy form.

Why is the two is one, one is none concept so important?

You may still think two is enough; there is no reason for any more. That may be true, but what if it isn’t? Imagine the simple scenario of an autumn hike. One of your party falls and injures themselves. They need medical attention. Your party splits up with one or more heading back the trail until they find a cell signal to call for help.

The group did have two flashlights, but after the split, each group has one. This is great until you realize the batteries are dead in one, or it was damaged in the fall.

Now one group has none, and it’s likely to get dark before you reach the trailhead.

If you think that is unrealistic, consider the following everyday scenarios that can easily deplete your emergency supplies:

• Your child goes camping with Scouts. At the drop-off point, they realize they forgot their pocket knife (first aid kit, fire starters, whatever). Being prepared, you pull one out of the car bag.
• At the playground, a child skins their knee and needs bandages. You use some from your bag.
• At sports, your child twists their wrist / ankle very slightly. The only thing that makes it “all better” is wrapping it with some of the self-sticking bandages from your emergency bag.
• You have one unopened bottle of water left to share with your sick child. You use the water bottle / cup out of your emergency bag to avoid sharing germs, later taking the bottle / cup into the house to wash.

In all those instances, it’s easy to forget and never replace the missing items. That’s an easy thing to do when times are good, and your safety and survival aren’t dependent on a flashlight, bandages, or a pocket knife. As a prepper, though, we keep worst-case scenarios in mind — times that might now allow for easy replacement of vital tools and gear.

Applying This in Your Kitchen

Since the kitchen is almost always the busiest room of the house, it makes sense to consider how you might plan for backups to your most important appliances.

If you have just one can opener or only one set of measuring cups, you’re asking for trouble! Start with the basics. A manual can opener is the obvious backup if your electric one ever dies, but it’s also just smart to own even if you never lose power, since electric can openers fail more often than people expect.

Keep a backup set of kitchen knives, even cheap ones, in case your good knife goes missing or needs sharpening at exactly the wrong moment. If you cook with propane or rely on one stove, think through what you’d actually do if that single heat source failed. As I write this, my oven needs a new sensor, so I’ve been using my Air Fryer for small baking projects instead. Most small kitchen appliances have multiple uses, some you may have never considered.

The same thinking applies to anything in your kitchen you depend on daily without a backup plan: a coffee maker, a way to boil water, a method for preserving food if the power goes out for an extended stretch. None of this means buying two of everything in your kitchen. It means asking yourself, for the handful of tools you can’t do without and use every single day, what happens the day that one breaks.

Buy the Best Quality Backups Your Budget Permits

When we start out, many of our preps are often low-quality simply because we don’t know what we really need or what to look for to get good quality. These low-quality items often end up in various emergency bags. There isn’t necessarily anything wrong with that. Honestly, I’m fine with the low-quality hammer and wrench in my car bag because they are truly just-in-case items I never, ever expect to use. But for critical areas like water, staying warm, and signaling, ensuring you have at least one higher-quality item could be a matter of life and death.

Going back to the example of a butane lighter, the simple fact is that many of us have lighters we picked up in the checkout lane as impulse purchases. These are almost always low-quality, disposable items. In decades past, high-quality refillable lighters were more widely available because smokers used them, and there were a lot more smokers in the USA. These disposable lighters aren’t refillable, and they are relatively easy to damage.

We all have budgetary limitations. Tossing in two cheap Mylar emergency blankets as backups for a higher-quality wool blanket or disposable lighters as back-up for storm-proof matches is perfectly reasonable.

A Final Word

Skill and gear redundancy is good advice and a sound survival principle. Identify the gear and other goods your survival depends upon and then begin adding back-ups. You won’t be sorry.

Originally published February 4, 2016; updated by The Survival Mom editors June 2026. With contributions from Jim Cobb.

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