david blanchette looked in to this as well with his own study .
Section 7: Conclusions
In this paper we use various government survey data and perform an analysis to more accurately
estimate the cost of retirement. We note that while a replacement rate between 70%
and 80% is likely a reasonable starting place for most households, the actual replacement goal
can vary considerably based on the expected differences between pre- and post-retirement
expenses. We also find that retiree expenditures do not, on average, increase each year by inflation
and that the actual “spending cure” of a retiree household also varies by total consumption,
whereby households with lower levels of consumption tend to have real increases in spending that
are greater than households with higher levels of consumption.
When combined, these findings have important implications for retirees, especially when estimating
the amount that must be saved to fund retirement. While many retirement income models use
a fixed time period (e.g., 30 years) to estimate the duration of retirement, modeling the cost over the
expected lifetime of the household, along with incorporating the actual spending curve, result
in a required account balance at retirement that can be 20% less than the amount required using
traditional models. In summary, a more advanced perspective on retiree spending needs can
significantly change the estimate of the true cost of retirement.
https://corporate.morningstar.com/ib...Retirement.pdf