Purpose, Applicability. The purpose of this section is to regulate and limit the continued existence of uses and structures established prior to the effective date of these regulations that do not conform to these regulations. Any nonconformity created by a change in the classification of property or the text of these regulations shall be regulated by the provisions of this section, with the "effective date" referenced below being the date the text of these regulations or the Zoning Map is amended to render a particular use, structure, or lot nonconforming. Many nonconformities may continue, but the provisions of this section are designed to curtail substantial investment in nonconformities and to bring about their eventual improvement or elimination in order to preserve the integrity of these regulations.