Overall, you are looking for a backpack that is sturdy and durable. You want one that will hold all your gear, yet be easy to carry. You also want to feel comfortable wearing your backpack.
There are two main types of backpacks - internal frame and external frame. Internal frame backpacks have the frame on the inside. External frame backpacks are backpacks that have the frame on the outside.
Internal backpacks fit snug against a persons back which makes them easier to carry than an external backpack. A person will have a natural sense of balance with an internal backpack so they are good for both on or off trail. The smaller size means they carry less, though. They also do not have as many pockets as an external backpack.
With an external backpack the actual pack bag is hung on the frame. They are usually rather large and extend above the head when worn. They usually have a lot of pockets and allow for space between the back and the pack for excellent ventilation. An external frame is suited to carrying heavy loads, but should be used on-trail only. They have a high center of balance so they make falls very easy if a person is on uneven ground or tries to bend down.
Choosing between internal or external frames involves considering a few factors about each and considering your own needs. You need to determine the average load you carry. Consider if you need a lot of pockets or compartments. You should think about your typical backpacking trip and what type of terrain you usually travel on. These things will help you determine which type of backpack is best for you. Generally speaking, external backpacks are good for heavy loads and trips on trails and smooth terrain and internal backpacks are good for smaller loads and for more diverse and rough terrain.
Both types of backpacks come in a range of styles and colors. Both can work wonderful for a backpacker, but finding your best backpack depends on your personal needs. Make sure you try out the backpack and make an informed decision to insure you get the backpack that is best for you and your needs.
