The 4% rule just survived its first real decade. Barely.

The first big FIRE cohort quit their jobs in the mid-2010s with one instruction taped to the portfolio: withdraw 4% the first year, adjust for inflation, done. That cohort has now lived through the decade everyone warned them about, and the results are in.

The headline says the rule survived. The details say anyone retiring in 2026 should be nervous rather than comfortable.

What the decade actually looked like

A violent bull market ran roughly five years before the first real stress arrived. That ordering matters more than most people understand. The 2020 COVID crash looked terrifying on a daily chart and recovered too fast to threaten a 40-year plan. The genuine stress test was 2022, when stocks fell, high-quality bonds fell, and inflation ate the withdrawal dollars all in the same year.

That joint shock is the scenario the 4% rule research always worried about, with one wrinkle: it landed in years five to ten of retirement rather than year one. A retiree from 2016 had already banked five years of strong returns when it hit, and those early gains are what carried the plan through.

Which means the decade was a demonstration of sequence luck, not rule robustness. A 2021 retiree got the same 2022 crash with no buffer, and their math looks very different.

What the survivors are doing differently now

The retirees who lived through this decade mostly changed their withdrawal behavior, not their portfolios. The patterns that showed up in retrospectives: skipping inflation adjustments in down years, keeping one or two years of spending in cash so a crash never forces a sale, and treating the 4% number as a starting point rather than a promise.

None of that is glamorous. All of it is arithmetic.

If you retired in 2016 with a million dollars, you took $40,000 the first year. After the inflation adjustments of 2021 and 2022, you were withdrawing around $48,000 by 2023 from a portfolio that had taken a real beating. The people still on plan are the ones who cut back to $43,000 in 2023 and let the portfolio heal.

The checklist worth running

Before trusting any withdrawal rate for a 40-plus year retirement, stress it against: a 2022-style joint stock and bond and inflation shock in years five to ten, a lost decade with zero real returns, and inflation running double the planning number for three straight years.

The full year-by-year walkthrough of the 2016 to 2026 path, with the actual portfolio numbers, is at Firenomics.

Cross-posted from Firenomics, where I write about FIRE math and withdrawal rate stress tests.