Since the late 20th century, construction companies have developed different brands of apartments while keeping the LOHAS, well-being, ubiquitous, and one-stop-living concepts in mind. From this point of view, this study intends to define the diverse space planning needs of apartment residents. The purpose of this study is to suggest optimum guidelines regarding the subject of space requirements and planning by conducting in-depth interviews of residents whose apartment floor size is between $66m^2$ (20 Pyong) and $165m^2$ (50 Pyong) and whose apartment is less than 5 years old. The major findings were as follows: (1) The shortage of storage space in different types of apartment housing units was found to be a chronic problem. Thus, closet sizes mustbe increased. (2) The size of the master bedroom needs to be decreased, whereas the size of the kitchen and dining room as well as the size of the second and/or third bedroom must be increased. More space is required in common areas occupied by the family and larger closets are needed. Less space is required for the master bedroom.