
Bike accessories make owning and maintaining a bike much easier than they would be without. Bicycles are notoriously specific about their fastenings, and they can be surprisingly complex as well. Some parts, such as the brakes, are usually fastened with hex nuts. Others, like the seat, feature quick release. Still others are assembled with screws.
Top end bikes feature remarkably few fastenings that require a tool to utilize. You can remove the seat and both wheels of most bikes via quick release technology. The technology is brilliant and simple. On an axle, it is a spring mounted device that has a large knob on either end. Attached to one end is a lever that controls the spring action. When open, you can rotate the lever end to tighten or loosen the grip. Once the grip is snug (but not tight) simply flip the lever to the closed position to lock the axle in place. This is one of the most convenient innovations in bike accessories in the past twenty years.
Prior to this, bike wheels were attached with nuts, which meant that you needed at least two properly sized crescent wrenches to take off a wheel and change a flat. Out on the trail, this is a huge hassle. You have to have the bike propped up and stable (an upside down bike does not breed stability). There were a host of bike accessories that aimed at helping towards that end.