Your ancestor might have always lived in the house that is presently at 1234 North Apple Street, but 1234 North Apple Street might not always have been 1234 North Apple Street. It might have 345 North Apple Street or 1234 Broad Street. In some cities homes have been renumbered and street names have changed. Local libraries, courthouses or other organizations in the area may be able to assist you in determining if there have been changes over time.
Because you need to have the contemporary address when using certain records.