Unpaid carers face significant financial risks, yet how caring shapes financial wellbeing (FWB) over time has been poorly understood. Drawing on qualitative research with fifty unpaid carers in Britain, purposively sampled across age, life stage, gender, caring intensity and socio-economic status, this paper applies and extends an ecological framework of FWB for the first time in a care context. It makes three contributions. First, it provides original empirical evidence showing that the financial consequences of caregiving are cumulative, uneven and experienced differently across the life course. Second, it develops a life course conceptualisation of carer FWB, highlighting dynamic interactions between individual circumstances, family situations and work, welfare and care systems. Third, it reframes policy debates by demonstrating how care costs are systematically individualised, making structural life stage sensitive interventions essential. Effective policy responses must therefore reflect carers’ differing needs across the life course and address cumulative financial risks. This includes support with saving and affordable housing for young adult carers; clearer pension information and protection from long term care related employment breaks in mid life; and more generous, flexible benefits and trusted care services. Our conceptualisation has international relevance in contexts where reliance on unpaid care is high, and formal support remains limited.