The figure quoted of 78 is what's known as "period" life expectancy. It's life expectancy from birth based on mortality rates in 2008, without any future improv

The figure quoted of 78 is what's known as "period" life expectancy. It's life expectancy from birth based on mortality rates in 2008, without any future improvements. In practice death rates are expected to continue falling over time. Looking at "cohort" life expectancy which allows for expected future improvements can give a considerably higher life expectancy. Also, it's not enough to look at the average. If life expectancy is 85 then you shouldn't plan to die at 85. It's more like rolling a die and having an age of death of any of 66, 77, 82, 88, 92, or 100 [1]. Maybe you need no savings, maybe you need lots. It's hard to plan for this without an annuity. [1] worked out a while ago so that it has the same mean, variance and four higher moments as life expectancy for a UK mortality table.