The decision to relocate in old age is intricately linked to thoughts and desires to stay put. However, most research focuses either on strategies that allow people to age in place or on their reasons for relocation. There is a need for more knowledge on very old peoples' residential reasoning, including thoughts about aging in place and thoughts about relocation as one intertwined process evolving in everyday life. The aim of this study was to explore what we refer to as the process of residential reasoning and how it changes over time among very old people, and to contribute to the theoretical development regarding aging in place and relocation. Taking a longitudinal perspective, data stem from the ENABLE-AGE In-depth Study, with interviews conducted in 2003 followed up in interviews in 2011. The 16 participants of the present study were 80-89years at the time of the first interview. During analysis the Theoretical Model of Residential Normalcy by Golant and the Life Course Model of Environmental Experience by Rowles & Watkins were used as sensitizing concepts. The findings revealed changes in the process of residential reasoning that related to a wide variety of issues. Such issues included the way very old people use their environmental experience, their striving to build upon or dismiss attachment to place, and their attempts to maintain or regain residential normalcy during years of declining health and loss of independence. In addition, the changes in reasoning were related to end-of-life issues. The findings contribute to the theoretical discussion on aging in place, relocation as a coping strategy, and reattachment after moving in very old age.