Turning a nest egg into a paycheck that lasts 30 years.
Two retirees with identical portfolios and identical average returns can have wildly different outcomes — if the order of returns is different. A big loss in the first 5 years of retirement is devastating because you're withdrawing from a shrunken portfolio. The same loss 10 years later barely matters. This is sequence-of-returns risk, and it's the single biggest danger to early retirement years.
Bill Bengen's original 4% rule — withdraw 4% in year 1 and adjust for inflation — was built to survive the worst 30-year period in US history. Updated research (including by Bengen himself) suggests 4.5–4.7% is more realistic for most cases. Guyton-Klinger "guardrails" can push initial withdrawals even higher by adjusting spending dynamically based on portfolio performance.
The bucket approach divides retirement assets by time horizon. Bucket 1: 1–2 years of cash for current spending. Bucket 2: 3–10 years in bonds. Bucket 3: 10+ years in stocks. As cash drains, bonds refill it; as bonds drain, stocks refill them during good markets. Psychologically it helps retirees stay invested through downturns — which is usually the whole point.