In Duncan v. Middlefield (1986), 23 Ohio St.3d 83, 23 Ohio B. 212, 491 N.E.2d 692, the Supreme Court stated: "While existing definitions of 'practical difficulties' are often nebulous, it can safely be said that a property owner encounters 'practical difficulties' whenever an area zoning requirement (e.g., frontage, setback, height) unreasonably deprives him of a permitted use of his property. The key to this standard is whether the area zoning requirement, as applied to the property owner in question, is reasonable. The practical difficulties standard differs from the unnecessary hardship standard normally applied in use variance cases, because no single factor controls in a determination of practical difficulties. A property owner is not denied the opportunity to establish practical difficulties, for example, simply because he purchased the property with knowledge of the zoning restrictions. "The factors to be considered and weighed in determining whether a property owner seeking an area variance has encountered practical difficulties in the use of his property include, but are not limited to: (1) whether the property in question will yield a reasonable return or whether there can be any beneficial use of the property without the variance; (2) whether the variance is substantial; (3) whether the essential character of the neighborhood would be substantially altered or whether adjoining properties would suffer a substantial detriment as a result of the variance; (4) whether the variance would adversely affect the delivery of governmental services (e.g., water, sewer, garbage); (5) whether the property owner purchased the property with knowledge of the zoning restriction; (6) whether the property owner's predicament feasibly can be obviated through some method other than a variance; (7) whether the spirit and intent behind the zoning requirement would be observed and substantial justice done by granting the variance." Duncan, at 86.