Backpack Capacity

Capacity is how much equipment will your pack hold. Capacities are usually measured in cubic inches and typically range from

You might think, like I did, you should just purchase the biggest one you can find. This way you could use it for small trips and large trips. There are two problems with this. First, a larger capacity backpack weighs more. Second, if you have all this extra capacity, you are tempted to take things you don't need.