<p>Parents of individuals with multiple disabilities, including those with Rett syndrome (RTT) provide prolonged caregiving and take on lifelong responsibilities for their child. Therefore, the parents’ ability to develop and sustain wellbeing throughout the years is crucial. To support them in this, knowledge about what affects them in different life phases throughout the years is important but limited. We aimed to explore the experiences of parents of individuals with RTT across different ages and phases of life, and how these experiences have affected them and their wellbeing. Using a phenomenological hermeneutic approach, we conducted an exploratory qualitative interview study with 25 parents of various ages of 12 individuals with Rett syndrome. The parents experienced a lifelong sense of having the principal responsibility for their child’s health, wellbeing, and quality of life, which affected them diversely, depending on the life phase they were going through. Over time, the parents accumulated experiences in different areas and situations that helped them manage similar future challenges. However, over time the extensive caregiving demands could also lead to exhaustion. Providing demanding care for many years, continuously advocating for the child, and witnessing the child’s struggles over time affected the parents’ wellbeing, albeit differently across life phases.</p>