Please note: I do NOT get paid to review or advertise products, I'm just sharing what I've learned and experimented with in regards to bag size, style, type, etc., in the hopes that it will help you decide what's right for you. In addition to that, these recommendations are geared towards minimizing your footprint for long-term, international travel; and while the same tools and methods will work for short-term or domestic travel, they may not be nearly as applicable, beneficial or realistic.
Your backpack will always be a personal choice, but my recommendation is to keep it as small, simple and cheap as possible - your "backpack" will get a lot of wear and tear, and the cheaper it is, the less you'll worry about losing it or replacing it as it wears out (and it will wear out!)
For each bag type/size, I'll tell you what I loved and didn't love, and why I settled on a small hiking backpack.
For a quick overview, I've traveled with the "traditional" 55-65L backpacks (REI if you're curious), a
But before we get into that, ask yourself the following questions..
What's the minimum size bag you need to fit everything you need?
If you're attempting to follow the Minimalist Method and wash your clothes every day, you can drastically reduce the size of your bag; for advice on what to bring or not bring, check out What YOU Should Pack, and then look through the Gear and Clothes section for tools and gadgets that can significantly reduce your need for space.
Once you've figured out how many clothes you'll be bringing, you can then narrow down your bag search based on other factors such as...
Will you be hiking or walking a lot? - Consider a hydration or hydration-compatible backpack
Will you be spending a lot of time on or near water? - Consider water-resistant bags/backpacks, waterproof electronics bags or waterproof laptop sleeves
Will you have your laptop? - Consider laptop sleeves, dry sacks or laptop-specific bags
And now, onto the various types of bags and backpacks you're probably considering..
"Traditional" 55-65L Backpacks
I won't go into the details here, I think it's obvious I'm a proponent of packing the bare minimum, but to give you an idea of what I hate about large bags..
Pros of large (45-70L) backpacks..
They give you ample space for everything you could possibly need; two weeks worth of clothes, multiple pairs of shoes, hiking, camping and cooking gear, space for gifts for friends and family.
Cons of large backpacks
They're expensive; and the more you spend on your bag, the more time you'll spend worrying about whether or not it's safe at your hotel or hostel.
They're bulky - you'll constantly struggle to find places to store your luggage, since you can't take it with you on day trips or half days, and you may struggle to fit that big bag in the limited storage space provided by hostels.
They're heavy and limit your flexibility - the second you start moving, that bag becomes a burden, even if it's just a "travel day" - lugging it around is annoying at best and painful at worst.
They effectively invite you to pack more than you need, it's no secret I'm a proponent of packing the bare minimum, but it's hard to imagine even filling a 40L bag with useful things.
If you're the digital nomad type, you may like and prefer the professional look and built-in protection of a laptop bag, but I've found myself regretting the purchase for a few reasons.
They're expensive, and the last thing I want on a long-term trip is to constantly be worried about my nice, new $200 laptop bag.
They scream "laptop" by design - if and when I bring my laptop on long trips, I actually don't want people to know I have a laptop, I'd rather not invite unwanted attention, even if it's safely locked up in a storage locker.. and when I'm on the move, a low profile bag is always preferred.
On the plus side, laptop bags are designed to protect your money-maker and keep your things well-organized; they look amazing and frequently come with well-thought-out design considerations like RFID protected pockets, adjustable/hidden straps, expansion pockets, and water-resistant materials, etc.
If your laptop is your life, and the above considerations don't concern you, there are a lot of options.. I'm a fan of Aer, Nomatic, Peak Design, and Gravel bags; or do the typical google search thing and find something you love. Also feel free to check out my post But I NEED My Laptop to determine if bringing your laptop is absolutely required.
Lastly, if you decide on any other bag type, but still want extra protection for your laptop, consider a waterproof laptop sleeve like the Aqua Quest Storm.
I started researching waterproof bags as my go-to for long-term travel, but I'm not sure if the reasons are completely obvious, so I'll give you a couple examples..
I once rented a motorcycle in Costa Rica, and while riding back to San Jose to return the bike, got caught in a tropical downpour, I had to ride to get "home," but was completely soaked head to toe, bag and all.
Our boat broke down off the coast of Cozumel in massive winds and waves, everything we brought had to be transferred to another boat, only there was no way to keep the boats close, so we had to jump in and swim to the rescue boat - again, everything soaked.
After checking out of a hostel near Iguazu Falls, Brazil, we took an unplanned boat ride near the falls, I had everything with me, but didn't realize we'd be going into (i.e. under) the falls, if there was ever a time for a waterproof bag, this was it.
I could keep going, but I think you get the picture... on the plus side, waterproof bags offer you peace of mind for those (planned or unplanned) water-based excursions; they're great for day trips to the beach, waterfall hikes, hot spring soaks, lake-side paddle boarding, boat outings, etc. however...
What I don't like about waterproof bags, is how heavy and inconvenient they become when you're doing anything other than water-based activities.. I've come to prefer (and require) easy-open bags with either a clam-shell or butterfly opening - versus the roll-top design inherent to any waterproof bag. Instead, I've opted to use smaller, light-weight dry sacks for all the electronics inside my backpack, which provides both flexibility and organization, while getting the same peace of mind as you would with a fully waterproof backpack. You can see how I pack here.
I'm an advocate of hydration or hydration-compatible backpacks, although my current backpack doesn't fall into that category; and I would mention saving the planet from water bottles, but the truth is that you will want to or have to buy filtered watered in many (if not most) of the countries you visit, so you may not be saving anything - but at least with a hydration pack, you can buy large water jugs and fill your hydration pack at the hostel.
Alternatively, you may want to opt for a small, collapsible water bottle for your daily outings, I'm a fan of the 25oz (750ml) Hydaway water bottle, due to its soft, silicon construction, versus the Vapur Flexible water bottle, with its Polyethylene (i.e. hard plastic) construction, which I constantly feared cutting my hands on when I reached into my bag; you might also consider the 1L Hydrapak Stow if you're looking for an ultra-lightweight, water filter-compatible option.
Despite the already small, daily-use backpack, I sprung for a low-profile, semi-waterproof chest sling bag; there's something comforting knowing that your most valuable possessions are tied tightly to your chest when you're on long trips or falling asleep on a train.
It may take some trial and error to find one you love, I tried the Osoce anti-theft bag, the Zomake anti-theft bag, the Weiatas anti-theft bag and the Waterfly sling chest bag, before finally settling on the Topnice chest sling bag, due to material/fabric comfort alone.
Another item that I love and have used used hundreds of times - although recently I haven't needed to pack it - is an ultra-compact, compressible day bag. I've had an 18L Sea-to-Summit Nano Pack that I've used for 15+ years, and it's still in great shape, but there's an Amazon Basics option and a water-resistant Osprey option as well; I doubt you can go wrong with any of them.
Hiking Backpacks (My Personal Preference)
As you've maybe seen in other posts, I travel with a 21L Mystery Ranch backpack (shown here) - it's small, comfortable and light enough to hike with.
I've found "comfortable enough to hike with" to be the best determining factor for selecting a minimalist backpack, it's comfortable when you're on the move and packing everything, and works just as great as a day bag when you're settled in a city for days, weeks or months at a time.
This bag does come with a small laptop (or iPad) sleeve that fits my 13in laptop perfectly, although you wouldn't be able to go much bigger, and while it's perfect for my needs, I don't expect it to be perfect for everyone.
Benefits of hiking backpack..
Perfect for daily use and packing all your belongings when you're on the move
Easily replaceable if it gets lost, damaged or stolen - the nearest outdoor gear or sports store should have many options
Generally inexpensive, usually under $100 to replace in a worst-case scenario
Many hiking packs are hydration-pack compatible, with all the benefits mentioned above
Cons of a hiking backpack..
Extremely limited in how much you can pack (but that's why you're here, isn't it?)
No built-in laptop protection - despite being able to fit small laptops, there's generally not a lot of padding for your money-maker
A lot of them are ugly - at least in my opinion - it can be difficult finding a bag that looks decent whether you're hiking, hitting the beach, exploring a city or hitting a coffee shop to work
Not a lot of internal organization - most hiking packs are simple by design, but this can be annoying when you prefer to have specific pockets for all your stuff
There are thousands of options to choose from, and it completely depends on your personal list of essential items, which you'll need to decide on before you even choose a backpack. So before you go looking for the perfect bag, ask yourself these questions..
What's the minimum size bag I need to fit everything I need?
Do I need my laptop and/or do I need laptop protection?
Do I need a waterproof bag or can I use a dry-sack for my electronics?
Do I want the flexibility (and inherent limitations) of a small backpack?
Do I want lots of internal organization/pockets for all my things?
Read Next: The Minimalist Method - How I keep my pack small and maximize flexibility