Among the unique characteristics of the special assessment is one that makes a special assessment particularly onerous for ordinary citizens. A special assessment levy enjoys a legal benefit known as a "presumption of validity." This means that it is much harder and usually, much more expensive to appeal than the "ad valorem" property tax most citizens are familiar with. This happens because it is difficult for the ordinary citizen to recognize that an error in the special assessment procedure or methodology has occurred and the resources a taxpayer must use to fight a special assessment levy are more expansive and costly than resources to fight an improper "ad valorem" tax on their real estate.