The aging workforce demands evidence-based human resource practices that lengthen working lives. Building on the Conservation of Resources theory (Hobfoll 1989), we investigate which organizational practices are indispensable for expanding older workers' occupational future time perspective (OFTP)—people's perceived opportunities and remaining time at work (Zacher and Frese 2009). A necessary condition analysis of survey data from 3077 workers aged 50+ in nine countries tests nine domains of the Later Life Workplace Index (LLWI) as potential minimal viable practices. All domains exhibited statistically significant necessity effects; however, using the conventional threshold (Dul et al. 2023), only later life supportive leadership and adaptive work design reached the level considered meaningfully necessary. The remaining domains showed smaller, near necessity effects, suggesting a pattern of partial necessity across HRM practices. Exploratory analyses along the Tightness–Looseness cultural continuum suggested that necessity thresholds tended to be higher in culturally Tight than Loose societies, highlighting the importance of context-sensitive HRM. This study refines theorizing on career sustainability, introduces necessity logic to the work and aging literature, and offers managers evidence-based tools to prevent insurmountable shortcomings. Failure to meet the identified LLWI thresholds will typically result in suboptimal OFTP.