If an insurer assumes that insureds will, on average, live longer than previously expected, the mortality cost built into life insurance premiums generally:

Explanation

Longer expected lifespans mean death claims are paid later and, on average, the insurer holds and invests premiums longer, so the mortality cost per year of life insurance tends to decrease and premiums can fall. Rising longevity would not raise mortality cost. Mortality does not stay the same when the underlying assumption changes. And mortality never becomes irrelevant, since it is one of the three core pricing factors. This is why improving life expectancy has historically lowered life insurance rates.