Once a taxpayer has recognized a problem exists, the difference in procedures to appeal a property tax and a special assessment levy makes a special assessment appeal much more difficult. Whereas, "ad valorem" tax appeals can often be made at a local level without any professional help, special assessment appeals often require the assistance of attorneys, engineers and other consultants. Furthermore, a taxpayer often has the opportunity to protest a property tax assessment annually. In the case of most special assessments, there is usually a very short window of opportunity to appeal and if the window is missed, there can be little recourse available.