"... the monetary salaries of private individuals are of three primary sorts: lease, benefit, and wages. Customary citizens will at last compensation their expenses from something like one of these income sources. The public authority might plan that a specific duty should fall solely on lease, benefit, or wages - and that another assessment should fall on each of the three private pay sources mutually. In any case, many expenses will definitely fall on assets and people altogether different from those planned ... Good charges meet four significant models. They are (1) proportionate to salaries or capacities to pay (2) certain rather than inconsistent (3) payable now and again and in manners advantageous to the citizens and (4) modest to oversee and collect. "[48]