<prompt> Human: Ive often heard the 4 Withdrawal Rule cited as good advice from intelligent people whom I have no reason to doubt. But it seems as though it doesnt take into account the effects of inflation, which would make it pretty terrible advice. Am I missing something obvious?Assistant: The Trinity Study behind the 4 rule assumed the withdrawal amount at outset would be adjusted each year for inflationHuman: Right, but doesnt that mean the withdrawal amount actually goes up slightly every year?I think what Im stuck on is that an inflation adjusted average return of 7 as DeluxeXL pointed out is not really the same as examining a range of 15 year rolling returns. The latter paints a picture where you could see anywhere from 3.5 to 20 before inflation.To me that feels more like saying the 4 rule might be totally fine, or could lead to financial ruin, depending on your luck. Id love to see a study that quantifies the likelihood of each outcome.  <response>: I recommend you read the Trinity Study and its updates. What it did was pose the question, Suppose we take a fixed percent of nest egg and then always take the same amount adjusted for inflation for 30 years, regardless of how well or poorly the market did. What is the likelihood that the result of doing that would lead to portfolio hitting 0 within 30 years? They backtested using historic data of 30 year rolling periods. Running all these simulations, they then looked at whether there was a percent figure low enough to avoid the catastrophe of the portfolio going to zero too soon. Thats where the 4 figure comes from. Its from backtesting lots of historic 30-year spans. It is not a law that must objectively hold true in future. 