Many people underestimate the risk of developing a disability in later life and needing long-term services and supports (LTSS). Using microsimulation modeling, we estimate that more than one-half (57 percent) of Americans turning 65 today will develop a disability serious enough to require LTSS. About one in five of all adults (22 percent) will need help for more than five years. On average, an American turning 65 today will incur $122,400 in future LTSS costs, measured in today’s dollars. Families will pay more than one-third (37 percent) of costs themselves out of pocket, with the rest covered by public programs and private insurance. Although most people with LTSS needs will spend relatively little on their care, 15 percent will spend at least $100,000 out of pocket for future LTSS. Many family caregivers also provide substantial unpaid care. Without that help, families and public programs would spend much more on LTSS.