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Retirement Planning

Safe Withdrawal Thinking:
why bad years early do permanent damage

In this chapter
  1. Why the average isn't the answer
  2. Why order matters so much
  3. Where the "4% rule" came from
  4. Where Plenee fits
  5. The takeaway

Why the average isn't the answer

Here is retirement's cruelest piece of arithmetic, in plain words: two people with identical savings, identical average returns and identical spending can end up in opposite places — one comfortable, one broke — purely because of the order the returns arrived in.

That's sequence risk, and it's why "the market averages X%" is nearly useless for planning a drawdown. Averages ignore order, and when you're spending down, order is almost everything.

Why order matters so much

While you're saving, order barely matters. Contributions buy more shares when prices are low, and the average largely governs the outcome ($180,000 In, $610,000 Out: what 30 years of $500 a month does).

Spending down reverses the physics. Withdrawing during a downturn means selling more shares at low prices — and those shares never recover with the market, because they're gone.

A bad market in the first years of retirement, combined with fixed withdrawals, can damage a portfolio beyond what the recovery afterwards repairs. The same bad market arriving in year twenty of an identical retirement is a footnote. The early years are the fragile ones.

Where the "4% rule" came from

The famous rule traces to two separate studies that often get merged into one.

William Bengen's 1994 paper used US market data back to 1926 and a portfolio split evenly between shares and bonds over 30 years. He found the worst starting year in that history could still sustain withdrawals of about 4.15%, rising with inflation — he called it SAFEMAX. A separate 1998 study, known as the Trinity Study, tested a wider range of portfolios and time horizons and reached a similar answer.1

Together they're best understood not as a rule but as a finding about history: starting withdrawal rates around that level survived the worst sequences in US data. That's the result of a stress test, not a guarantee, and it's sensitive to its assumptions — how long you need the money, what you hold, and what you pay in fees. Hidden Fees on a $400,000 Balance Cost $3,800 a Year: where they are published's drag applies to survival math too, and both original studies leave fees out.

What lasts is the thinking:

The actual plan — the rate, the limits you'd adjust within, the floor — is the professional conversation this chapter is designed to make you fluent in. It's arguably the single most valuable conversation in the curriculum.

Where Plenee fits

Plenee's contribution is the inputs and the early warning: honest spending numbers (coreFLOW against lifeFLOW — your flexibility map, coreFLOW vs. lifeFLOW: the 2 questions that sort obligations from choices), the drawdown tracked against the plan's limits, and enough visibility of your cash layer to show whether a bad year's withdrawals are hitting the buffer or the portfolio. You can't control the sequence. You can see your exposure to it.

The takeaway

Averages ignore order, and spending down runs on order — bad years early do permanent damage that bad years late don't. Think in sequences: stress-tested rates as a starting point, flexible spending as the live defense, and cash floors so downturns don't have to be sold into. Build the real plan with a professional. Whoever plans for the worst sequence gets to enjoy every better one.

Also in these situations
  1. Five Years From RetiringAverages ignore order, and spending down runs on order — bad years early do permanent damage that bad years late don't.
Sources
  1. William Bengen, "Determining Withdrawal Rates Using Historical Data," Journal of Financial Planning (1994) — using US data back to 1926 and a 50/50 stock-bond portfolio over a 30-year horizon, found a ~4.15% SAFEMAX. Cooley, Hubbard & Walz, the "Trinity Study," AAII Journal (1998, not Journal of Financial Planning — a common misattribution) — tested a fuller allocation/horizon grid and reached a similar conclusion. Both use only US historical data and generally exclude investment fees. ---

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