If you are a frequent backpacker, it is unlikely that you don’t know the importance of carrying the right kind of rucksack. The functionality of a rucksack is more important than its looks because the right rucksack will literally save you from backaches and hip aches.
1.    Waterproofing: As far as possible, buy a rucksack that’s made of water-proof/ water resistant material. To ensure that water doesn’t enter through the seams and openings, carry a rucksack cover or use a water proof rucksack liner to keep important things dry inside.
2.    Frame: Buy a rucksack which has either an internal or an external frame, since they transfer a lot of the weight from your shoulders to your hips. This results in a better center of gravity, which can make walking long distances comfortable.
3.    Shoulder Straps: Look for shoulder straps with good and comfortable padding (preferably a “honeycombed” synthetic material that feels like Gel) and that which is designed to handle around 30 percent of the weight. This ensures that the pack is balanced and the weight is transferred onto the hips. There should be a chest strap that helps prevent your shoulders from being pulled back and further help in distributing the load.
4.    Hip Belt: The hip belt is the main load bearing part of the rucksack. It should have good padding and help seat the pack comfortably and firmly on the hips thus minimizing lateral movement. . The clip on the belt should be sturdy and easy to engage, release, and adjust. Make sure the belt has a generous, soft and broad padding to avoid sore spots on sensitive areas that could become painful.
5.    Back pad: The back pad (the part of the bag the touches your back) and it should be made of a comfortably thick foam covered with fabric, to give maximum ease to your spine.
6.    Inner and Outer Pockets: This allows better organization of your provisions, gear and other backpack contents. Outer pockets are for items that you would use frequently during the hike. Make sure you don’t over stuff your outer pockets causing a shift of weight and making you uncomfortable.
7.   Extra Loops: Look for backpacks that have loops to hang extra gear if needed, these come in handy if you come access some items whilst trekking.
8.    Women’s Backpack: There are manufacturers of rucksacks which have harness systems like, hip belts, shoulder straps and the pack shape especially designed to fit the female form. So, ladies could opt for these for better comfort.
9.    Overall make of the rucksack: Ensure that the rucksack is made of durable fabric, has tightly stitched seams especially at stress and load bearing points (To test for this, pull on the seam where the straps are sewn to check how tight or loose the stitches are) and that the inside seams are bound (covered by fabric) so they are more durable. Last but not the least, look out for strong zips.
All in all comfort is the key word, and you will definitely have a hassle free experience with a good rucksack for company.