Kirchhoff's laws are usually considered as electrical current and voltage properties. Nevertheless, they are sometimes applied to nonelectrical systems. One way to increase their efficacy and range of applicability would be to show Kirchhoff's laws, and the properties deriving from them, as being independent of any physical system as far as possible. Some of these properties, derived exclusively from Kirchhoff's laws, are identified in this paper, along with systems that verify them; these systems are presented as examples. (Contains 9 figures.)