Biogerontology researchers face a fundamental definitional crisis that's hampering progress in longevity science. While lifespan has clear boundaries—birth to death—healthspan lacks consensus, creating research incomparability across studies. The traditional view equates healthspan with disease-free living, but this Danish analysis proposes a paradigm shift toward "homeodynamic space"—the capacity to maintain physical and mental independence regardless of underlying conditions. This reframing acknowledges that many people live meaningful, functional lives despite chronic diseases through medical, technological, and social compensations. The distinction matters enormously for aging research priorities and intervention development. Current healthspan metrics may prematurely "end" at disease diagnosis, missing decades of potentially high-quality life that modern medicine enables. This conceptual evolution could redirect research from purely preventing disease onset toward optimizing functional capacity and independence throughout extended lifespans. The framework suggests healthspan should be measured not by absence of pathology but by preservation of autonomy and meaningful engagement. While this editorial offers valuable conceptual clarity, the field needs empirical validation of homeodynamic markers and standardized independence metrics to operationalize this more nuanced, realistic approach to healthy aging.