What If I Live to 100?

Outliving your money is the fear underneath most retirement planning. A plan that’s comfortable to 90 can look very different stretched to 100. This recipe tests how your plan holds up over a long life.

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The quick version

1. Raise the plan end age (or turn on stochastic mortality).
2. Save it as a named strategy — "Plan to 100."
3. Run Comparison against your baseline — does the plan still hold over the longer life?

Step by step

1. Stretch the horizon. On the Household tab, raise the plan end age (to 100, or even 105 to be extra cautious). Remember this is a planning horizon, not a prediction — a higher number simply means your money has to last longer, which is the conservative choice.

2. Or model longevity directly. Switch mortality to Stochastic to see the full distribution of outcomes across many possible lifespans, including the long ones. See Surviving spouse & mortality.

3. Save it as a named strategy (the Strategies button) — "Plan to 100."

4. Run Comparison on the Compare tab; with Compare against baseline on (the default), your baseline is drawn automatically beside the longer-life version. Load Baseline (⤺) returns you to your plan.

What to look at

• Success Rate over the longer horizon — the most direct measure of longevity risk. A plan that’s solid to 90 but fragile to 100 is telling you something.
• The ruin-probability chart — watch how far out the failures cluster; a long life pushes more simulations toward late depletion.
• Late-plan trajectory — does the portfolio thin out dangerously in the final decade?

If a long life strains the plan

Longevity is exactly what guaranteed, inflation-protected income is for:

• Delay Social Security toward 70 — the larger lifetime check is essentially longevity insurance.
• Use a Guardrails withdrawal method so spending eases in bad stretches rather than draining the portfolio.
• Trim or phase spending, especially in the early years.
• Consider that real spending often falls in mid-retirement (before healthcare rises) — model that with spending phases rather than assuming flat spending for 35+ years.