Housing adaptation is increasingly recognized internationally as a critical area for intervention, addressing the challenges posed by an aging population and the rising demand for transforming the existing housing stock into more inclusive, safe, and comfortable spaces. These environments must accommodate the dynamic nature of functional decline associated with aging by adopting a life-span approach and designing care-ready spaces that anticipate the onset of chronic diseases alongside daily and home care activities. Prioritizing the adaptation of existing housing not only extends the operational life of buildings but also aims to curb urban sprawl and advocate for more responsible land use. This goal requires a design strategy focused on minimal intervention and the promotion of flexible and reversible solutions, integrating smart technologies within a life-cycle perspective, while minimizing environmental impact. The awareness of how environmental comfort (visual, acoustic, thermal, and indoor air quality) impacts the older adults’ quality of life, their health, and their well-being should be considered together with the adoption of technical solutions with low environmental footprint. Consequently, the complex array of requirements that a living space must fulfil mandates the identification, systematization, and implementation of support tools for home adaptation projects to define the most appropriate characteristics of the technical elements, finishes, and furnishings. This study aims to contribute to the development of criteria and strategies for designing sustainable adaptability interventions in housing tailored to the diverse needs of older adults throughout their life course. Particular attention has been paid to technical solutions to improve environmental comfort in a global vision of the older adult’s well-being, even in compromised health conditions. In particular, the photometric characteristics of finishing materials and furnishings, environmental control devices and systems, and flexible interior partition technical elements that improve acoustic comfort and are based on dry construction systems designed to be easily disassembled, facilitating reuse and recycling of components, were observed. The results obtained from systematizing observed best practices that effectively integrate comfort with circularity principles suggest criteria and design strategies and, at the same time, foster sustainable adaptability interventions inherently connecting the dual design perspectives of meeting life-course needs and extending the lifespan of housing.