The term lifestyle, which had first been set forth by Alfred Adler in 1929, quickly entered other areas of science. Different scholars have stated various definitions of this term in different scientific fields. The general definition of this term is the social and cultural changes in the everyday life of the people. The major changes in lifestyle in the contemporary times have been made by the increased efficiency of modernity and technology in people's lives. Modernity entered Iran in Nasir al-Din Shah Qajar era; but, its effects in construction are seen in the last 50 years after the adoption of comprehensive urban plans. These changes have changed the content and function of the traditional home and turned them into apartments. The subject of the study is District 9, Tehran, which is located in the central axis of Tehran and has been less invaded by the rapid development. Thus, the gradual changes in the texture and housing in that area can be studied. The purpose of the study was to examine the changes in apartments in the last 50 years in Tehran. The main question was how the spatial changes of the elements of residential apartments in Tehran was. The results showed that among the changes the ratio of spaces - bedroom, living room, and dining room and kitchen - in the 10 and 15-year intervals, the ratio of the average kitchen size in residential apartments has not changed during 50 years. However, the ratio of the average size of the bedroom and living room and dining room spaces during this period has changed greatly, but regression to the initial point was obtained at the end.
