The 4% rule is not dead. Bengen (Journal of Financial Planning, October 1994) measured a 30-year worst-case starting rate: 4% of year-one value, then last year's dollars plus inflation, on 50/50 U.S. stocks and intermediate Treasuries. No 50/50 path died before year 33. About 3.5% never produced a life under 50 years.
Trinity Table 3 (Cooley, Hubbard, Walz, AAII Journal, February 1998) counts 41 overlapping 1926–1995 windows. Inflation-adjusted 4% succeeded in 95% of 50/50 and 100% stock cohorts and 98% of 75/25 — 39 and 40 of 41 U.S. paths, not a Monte Carlo probability. The chart is those cells.
FIRE changes the horizon, not the method. Kitces on Bengen 1996: the historical safe initial rate falls from 4.1% at 30 years to 3.5% at 45. Write a rule you will obey. If you will not take a 10% cut, do not start at Guyton–Klinger 5.2%. Start at 3.5–4.0%.
Run the same spending at 3.5% and 4.0% in Target FIRE on earlyfire.quest. Use the band.
Share of 41 overlapping U.S. cohorts, 1926–1995 (%)
Cooley, Hubbard, and Walz, AAII Journal, February 1998, Table 3. Inflation-adjusted withdrawals. 41 overlapping 30-year periods, 1926–1995. S&P 500 and long-term high-grade corporates. Numbers rounded to the nearest whole percentage. A 95% cell is 39 of 41 paths; a 98% cell is 40 of 41.