Behaviors are reusable across more than one application. These articles explain how to create useful behaviors to perform commonly used functionality.
Behaviors are a useful approach for adding an effect to a control, removing boiler-plate effect handling code from code-behind files. This article demonstrates using a Xamarin.Forms behavior to add an effect to a control.
Behaviors can be used to associate commands with controls that were not designed to interact with commands. This article demonstrates using a Xamarin.Forms behavior to invoke a command when an event fires.