Many of the tools come set with defaults. Perhaps the tool that you are most likely to want to set using defaults is the arrow line tool.
If you wish to draw this network diagram,
you have to create eleven lines and make the start and end points filled in white circles. Because the arrow line defaults to a line with a triangular arrow head, this means drawing eleven lines, selecting them individually and editing their properties to add the white circles OR set the default for the arrow line.
To set a default, you set a line to the desired type and then press the Set to Default button. Your selected defaults will be saved and used whenever you create another arrow line.
In the example above, the default arrow line was set to
Video - Setting Defaults