When you go on any trip longer than a walk or a short exploration for dinner, you are going to need a dayback. These include backpacks for school, top loaders, trail run packs and more. While they may look similar at first glance, it's best to ensure that you choose the pack that is best for you! **Choose a Panel Loader, or a Top Loader -Panel Loaders These bags have a main storage compartment that is accessed via a U-shaped zipper. Fully opened, one panel falls away like a flap. Because of that huge opening, this is great for being able to easily search for something. This is a great bag for organization. -Top Loading Simpler and lighter than the same sized pane loading model, they are easier to overstuff and pull shut with a drawstring in many cases. Some have extendable top lids great for storing extra gear (such as climbing gear) that you'll be using until you get to your climb location, and then allow you to make your bag smaller again. They also have a great side stabilization method, good for climbers and skiers! But, packing and locating gear inside a top loader can be really hard to do. **Choose a size - Personally, I go with a 30 liter (1,830 cubic meter) bag for hiking and the related activities I do. My friends that do trail-running stick to as little as 10 liters, and climbing bags typically reach 50 liters. ** Match Your Activity - For Day Hiking: 30 liters, side pockets, compartments for organization, hydration system enabled. -Scrambling/climbing: 40 liters, narrow profile, padded back, features like crampon patches and daisy chains, load stabilizing straps. - Ski touring: smooth, narrow profile, hipbelt/sternup strap, ski attachment capability, secure place for shovel, this will all depend on how much you are touring. -Trail running/adventure racing: water bottle pack, small daypack (less than 25 liters) or waist pack will be best. There are also some specialized packs out there that fit women specifically, hold hydration systems, have ventilated back panels, Lastly, don't go too cheap! There's nothing wrong with finding a good bargain, but make sure to choose a bag that has all the features it can have, and isn't going to fail on you. Quality, in the case of your daypack, is more important that price, so make sure to find the right compromise between the two!