A 40% Crash in Year 3 Costs You Almost Nothing. In Year 19 It Costs $116,000

Everyone worries about the crash. Almost nobody asks the only question that actually determines how much it costs them: when does it hit?

So I modeled it. Same plan, same crash, dropped into five different years. The spread between best case and worst case was over $94,000, and it completely changed which risk I actually worry about.

Not financial advice. This is a simplified illustration to show how one mechanism works – real markets don’t hand you a tidy 8% a year. Do your own research.

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The Model

Deliberately simple so you can follow it: $6,000 invested per year (about $500 a month), for 20 years, at 8% a year. Total contributed: $120,000.

Run clean, that ends at about $274,600.

Now I replace exactly one year’s +8% with -40% – a genuinely severe crash, the kind that makes the news for a decade – and leave everything else identical. Only the timing changes.

The Results

• Crash in year 3: ends at $252,400. Cost: $22,200
• Crash in year 5: ends at $233,400. Cost: $41,200
• Crash in year 10: ends at $196,900. Cost: $77,600
• Crash in year 15: ends at $172,100. Cost: $102,500
• Crash in year 19: ends at $158,100. Cost: $116,500

Identical crash. Identical plan. The version that hits in year 19 costs more than five times what the year-3 version costs.

The reason is almost dumb once you see it: 40% of a small balance is a small number. In year 3 there’s maybe $19,000 in the account, so the crash takes a few thousand dollars – and then seventeen more years of contributions and growth roll over the top of it. In year 19 there’s about $260,000 sitting there, so the same percentage takes six figures, and there’s no time left to grow back.

Then I Added the Rebound, Because Crashes Don’t Happen Alone

Real crashes are usually followed by strong recovery years. So I ran it again: the -40% year, followed by three years at +15%.

• Crash in year 3, with rebound: ends at $266,700. Total cost: $7,800 – about 3% of the plan.
• Crash in year 10, with rebound: ends at $222,100. Cost: $52,500.
• Crash in year 19, with rebound: ends at $167,900. Cost: $106,600 – the rebound arrives after the plan ends, so it barely helps.

Read that first line again. A once-in-a-generation crash early in a 20-year plan, with a normal recovery afterward, cost about 3%.

If you’re in the first third of your accumulating years, the crash you’re afraid of is close to a non-event – provided you keep contributing through it. That condition is doing all the work, which I’ll come back to.

What This Changed About What I Worry About

I used to worry about crashes generically. Now I worry about one specific thing: a crash close to the date I need the money.

That’s it. That’s the whole risk. It has a name – sequence of returns risk – and it’s the reason “stocks return 8% on average” can be true while two people with identical average returns end up in wildly different places.

Practically, it means the answer to “how much market risk should I take” depends far less on my personality than on my distance from the goal:

• 15+ years out: volatility is mostly noise, and a crash is arguably a gift – your scheduled contributions buy more shares. This is where the honest case for dollar-cost averaging actually earns its keep.
• 5-15 years out: a crash costs real money, but there’s still time. Keep going.
• Under 5 years out: this is where a crash can genuinely break a plan, and where I stop being brave with money that has a deadline on it.

None of that is a stock tip. It’s just noticing that the same asset carries a completely different risk depending on your timeline, and that a lot of nervous investors are worried at exactly the stage where they have the least to fear.

The One Thing That Breaks the Whole Model

Every number above assumes you kept investing $6,000 a year straight through the crash. Every single one.

If you stop contributing during the downturn, or worse, sell and sit in cash for two years waiting to feel confident, the math falls apart. You skip the cheap purchases, you miss the front end of the rebound – which is usually the sharpest part – and the year-3 crash that should have cost you $7,800 costs you a fortune instead.

So the actual risk in a crash isn’t the crash. It’s the behavior. And behavior is what you can prepare for in advance, unlike the crash itself:

• Keep an emergency fund that isn’t invested. If a lost job during a downturn forces you to sell at the bottom, the market didn’t cost you the money – the missing cash buffer did.
• Automate the contributions. A transfer you never see is far more likely to survive a scary month than a decision you have to make. Mine runs monthly into a broad index fund at Schwab and I don’t log in to watch it.
• Write down what you’ll do before it happens. A rule you wrote calmly beats a decision you make while panicking, every time. A big part of preparing for a financial winter is deciding in advance.
• Know your timeline. If you know your money isn’t needed for 18 years, a 40% drop is information about prices, not about your plan. Which is exactly why knowing your actual freedom number and date is worth the twenty minutes.

The Takeaway

A severe crash early in a long plan is a rounding error. A severe crash right at the finish line is the thing that can genuinely hurt you.

That asymmetry means the right amount of worry isn’t constant – it should grow as you approach the date you need the money, and it should be close to zero when you’re two decades out and still buying every month.

Most people have it exactly backwards: terrified at 30, complacent at 60. If you’re the kind of person who checks the math, run these numbers on your own contribution and your own timeline. The version of this in what compounding does decade by decade is the same coin, other side up.