【计】 估计寿命, 预期使用寿命
【化】 耐用期限
【经】 使用年限

expectancy individual expectancy chart life life for life life-preserver life span life-span night life life time life characteristic in life life-expectancy expectancy of life active life expectancy average life expectancy life expectancy at birth Life-time expectancy life-expectancy analysis average life expectancy at birth Expectancy generalized expectancy