Similar in function to backpacks, messenger bags ensure comfort to people carrying heavy and/or bulky items, while allowing easy access to the contents.
Messenger bags typically incorporate features that make them particularly suitable for cycling, such as fittings that make it easy to adjust the shoulder strap, quick release buckles, an adjustable hinged buckle, and the ability to attach a variety of accessories, such as lights, phone holsters, or U-locks. Contemporary stabilizing straps help to prevent the bag from shifting while riding. The top-opening one-strap design allows messenger bags to be easily swung around front so that their contents can be accessed without having to remove the bag.
Messenger bags are often used as a fashion accessory. While they can be found in the possession of either gender, they are often commonly employed by men in a function analogous to a woman's purse (that is, to carry bulky items that do not fit into pockets, or a large number of items, while doubling as a fashion accessory). Messenger bags have also become fashionable in urban environments, among cyclists and commuters. Many college and high-school students make use of them for fashionable and functional purposes, especially those who commute on bicycles. Many companies design messenger bags specifically for the collegiate market. Compared to a backpack, it is much easier to place and remove text-books, notebooks, essays and supplies from a messenger bag because they can be easily shifted to lie on the side of the body (or, if the strap is long enough, it will be there by default), granting the wearer better accessibility. Messenger bags also provide more weather resistance than traditional leather satchel-style school bags.