There are two general sizes for a bug out bag. The backpack and the hiking pack. Depending on what you plan to pack and the terrain you are taking you may want to choose one or another. Let's take a look at both.
Backpack
Backpack size doesn’t mean your kid's school bag. A serious outdoors backpack is a tough and rugged piece of gear. A backpack typically lacks a wide variety of features you'd find on a hiking pack.
Backpacks are smaller than hiking packs, but when packed properly they can contain a ton of necessary gear. Backpacks are smaller and therefore lighter as well. They are more maneuverable for use inside vehicles and in urban terrain.
Since backpacks stick out less from the body they are easier to move in and out of doors, hallways, windows and more. Backpacks are certainly better suited for urban environments, or if you know, you will be moving in and out of cars.
Hiking Packs
Hiking Packs are the best go-to for rural environments. They are built for this kind of work. In most cases, they also offer significantly more room than most backpacks.
Hiking packs can range from somewhat small and convenient, to absolutely massive packs that can hold a week's worth of goods. Hiking packs are often designed for long walks over rough terrain.
Hiking packs are outfitted with a wide variety of features that make it more comfortable to carry a heavy load for a long haul.
It’s substantially easier to carry three days worth of food, water, clothing, medical gear, and even shelter tools. This kind of pack is harder to use in and out of a vehicle and does take up a significant amount of room. From my experience hiking packs are difficult to use inside of buildings, especially if you are climbing through small hallways and doorways.
Sling Bags
Sling bags are a third option I am tossing up on this list, even though they often cannot carry three days of food, water, and other necessities. Sling bags often fit the category of “Get Home” bag.
A Get Home bag is a subset of the bug out bag. Since you can’t haul a Bug Out bag with you everywhere, you go you have a Get Home Bag. A Get Home Bag is a mini bug out bag designed to get you to your main bug out bag, which is likely at home.
A Get Home bag has the necessary supplies to get you from work to home, or from out and about to home, in the event of an emergency. A Sling bag is a small, compact bag that fits anywhere and is easy to use in and out of vehicles.
1 Days worth of supplies is easy to carry in something as small as a sling bag. Technically it's a bug out bag because you are bugging out to your main bag, family, and departure point.
Comfort
As someone who has hiked a lot, and I mean a lot, I will say that comfort is incredibly important. You could be carrying this bag on your back for days on end and if it's not comfortable you’ll be in pain very quickly. There are a number of features you should look for when it comes to comfort.
Wide Shoulder Straps
The wider the shoulder straps, the more comfortable they’ll be. Wider straps help distribute the weight more evenly. This creates less shoulder pain and generally makes carrying a pack way more comfortable.
Wide padded straps are a must-have for long-term hiking, and of course, long-term bugging out. Wide shoulder straps will make life good.
Hip Strap
Three days worth of survival supplies can get heavy quickly, especially if you are also packing a tent, cooking gear, and extra tools and equipment. Placing all that weight on your shoulders will become uncomfortable very quickly.
A hip strap helps take the weight off your shoulders and back and places the weight on your hips and thighs. This distribution will make life so much easier for you. My life changed the day I learned how to use hip straps properly.
Hip straps are often padded to prevent chafing, or made from wide webbing. This combination of features is almost always found in hiking packs but is slightly rarer in backpacks. Some military issue backpacks will have these hip straps and can be had cheaply on the surplus market.
Chest Clip
A chest clip is a nice little feature to have. A chest clip and strap attaches to both shoulder straps and clips in the middle. This keeps the shoulder straps in proper position and keeps the pack straps from sliding and moving. It really helps to counterbalance a heavy load.
The majority of people will love it, but for wide shouldered guys like me, they rarely fit. If you are a big guy with broad shoulders, you may need to find a chest or sternum clip extensions, which are easy to find and quite common.
Padded Backing and Frame
A padded backing is a great feature to have for carrying a heavy load for a number of reasons. First off padding is just comfortable to feel on your back. Second, padding often creates channels that allow air to flow between your back and pack that allows for a cooler, chafe-free carry.
Padded backing is also great for keeping hard and pointy items in your pack from being driven into your back. This decreases discomfort from coming from the pack.
A frame is something you are more likely to find in a hiking packing. Frames can be external or internal. These frames help support the pack and make carrying heavy loads easier for longer periods of time.
External frames are often stronger and put airspace between your back and the pack. However, external frame packs are often heavier overall. Internal frames are lighter but don't provide the same degree of support that an external frame will.
Adjustment and Lots of It
The ability to adjust everything is a great feature to have. You want to be able to adjust the shoulder straps, the chest strap, the hip straps and more. This level of adjustment makes life much easier.
The more you can adjust your pack the better it will fit you and the better it will be for long-term use.
Additional Features
Modularity
Modularity is a great way to enhance the ability of your pack. The most common modular platform will be through MOLLE webbing. MOLLE webbing allows you to attach accessories, pouches, and more to your pack.
This modular interface makes it easy to add accessory pouches for greater accessibility. A wide variety of packs now incorporate MOLLE and its incredibly common in the tactical pack world.
Hydration Bladder Pocket
Camelbak changed the world with the advent of the backpack mounted hydration bladders.
These days this is a common feature in many backpacks and hiking packs. On modern packs, you’ll find specialize pockets for hydration bladders with drinking tubes coming out of the bag for easy access to fluid while hiking.
Internal Organizational Ability
The inside of the bag is just as important as the outside. Several bags may come with internal hook and loop attachments for the attachment of pouches for great organizational ability.
The ability to organize a bag is very important and makes it easy to get to those important goods faster and easier.
Rear Stretch Pocket
A Rear stretch pocket is a simple pocket that is separate from the internal bag. This pocket is commonly used to store things like wet clothing, ponchos, rain catches, and other items you wouldn't want to expose the inside of the bag too.
