Lifecycle Consumption Models and Dispersion in Consumption
There are two major "qualifiers" to the life-cycle hypothesis (LCH). Both put forth by John Maynard Keynes in "The General Theory of Employment, Interest, and Money."

The first is the "precautionary effect," that people save more than the LCH would predict because they are uncertain about their future health, life span, medical bills, etc.

A second qualifier is that old people would want to leave a bequest, or legacy to their descendants, and therefore not spend all their savings.