First, get great insider info on my other sites if you are going toThailand, Borneo, or justbackpacking!
Choosing the right backpack for your trip is probably the single most important travel purchase that you will make before leaving home.
Your backpack will be your companion, your house, and the most important piece of gear accompanying you around the world.
There are many brands and styles out there, so apart from a few important considerations, the rest is up to your style of travel and preference.

Style

First, you will most definitely want an internal frame travel backpack.  There will be no need to attach things to the external frame unless you are primarily camping and carry bulky items like a bedroll.  Internal frame packs keep everything self contained and are definitely the most popular style for travel.
Next, you will have to decide on the size.  Carrying too much on your backpacking trip will drastically alter your experience (not for good!) and parking too much is the number one mistake that all new travelers make.  You can curb the chances of packing too much by choosing a smaller backpack – it simply won’t fit!
To get an idea of what you may be carrying, take a look at my backpacking packing list!

Size

3,000-5,000 cubic inches (50-80 liters) – is the most popular size for extended budget travel trips such as gap years, but if you can get away with a smaller backpack – do it!  Remember, never leave the house with a backpack completely full, it will never work!  You will actually be better off buying a slightly larger pack and not filling it to capacity.
An alternative option which works well is to buy a larger main pack and actually put a smaller, collapsible daybag inside of it, so that way you only have 1 bag to carry until you can drop the larger backpack and switch to the smaller day pack.

Durability

The two critical features on any backpack that are most prone to tear up are the straps and zippers.  Look for double stiching, good quality metal zippers, and buckles that don’t feel flimsy / fragile.  You can pretty well judge how prone a zipper is to locking up just by trying it a few times back and forth.
If you have to purchase a backpack before getting to inspect it, go with a respected brand that specializes primarily in just backpacks.
Good backpacks have ventilation systems or a netting that keeps the load off of your lower back so that your clothes will not sweat through. While this certainly helps comfort, it is also slightly more prone to getting torn up than just a simple back pad.

Fit

Along with capacity, you will have to decide on a size (small, medium, large, extra-large) for the pack frame itself.  Most men will end up with a “large” pack while women choose “medium” framed packs.  Gregory is one brand that builds specific backpacks to fit a woman’s shoulders rather than just making their packs smaller.
Regardless of the brand, size, or capacity – a backpack should be fitted to your body and feel comfortable when loaded with at least 50 pounds / 25 kilograms.  Your local outdoor store will have weights to let you try packs. Don’t worry, this is only a test; you won’t be carrying this much weight!
The average weight of a backpacker’s pack you meet on the road is between 26 – 33 pounds / 12 – 15 kilograms. The maximum checked bag weight for many budget airlines is 15 kilograms anyway – definitely do your best to keep your pack below that threshold.
Here’s how to fit a backpack properly:
  • A backpack’s weight should sit on your hips rather than pull down on your shoulders.  Weight should be close to your body, not pulling you backward awkwardly.
  • Different backpack manufacturers’ frames may correspond to different torso lengths, so check the pack’s technical specifications. For example, a 20-inch torso length may mean a regular size in one pack and a large in another.  To find your torso length, have someone measure from the iliac crest at the top of your hipbone to the prominent bone at the base of your neck (the seventh cervical vertebrae).
  • A pack should not be so much taller than you that you cannot look up without hitting the back of your head on the top of it.
  • You should be able to walk around with the pack fully loaded without sweating through.

Side or top loading

This depends entirely on preference and backpackers will debate it to the end.  Top loading packs are the most popular, but everything packs into them in a linear fashion so you have to pack based on when you will need to access things.  Sideloading packs open like a duffel bag, allowing access to all the contents in exchange for slightly more awkward handling.
There is no “perfect” decision for travel, it all depends on your personal preference!

Where to buy a travel backpack?

Aside from the obvious choices of online retailers and outdoor stores, check craigslist.org and alsotravel backpacks on Ebay for used or special deals. Many students and travelers come home from an around the world trip and need cash so they sell their backpacks.  Also, well known brands are tough enough that buying used is of little concern.
Buying your travel backpack is exciting, it is your largest trip purchase and will soon be your pride and joy when it arrives.
Check out my personal vagabonding blog to see what I’m currently doing with my travel backpack!