Ask “can I retire?” and you want one number back. The number is a comfort, and it hides more than it tells. Four things move the real answer, and only one of them is your balance.
Spending, far more than your balance
In our first case a household started with $840,000. Changing that starting balance mattered less than changing what they spent. An extra $8,000 a year of lifestyle spending, about $667 a month, moved the plan from lasting past 95 to running dry in the early 80s. Same portfolio, same markets. Your balance is what you have. Spending is what you steer. It has its own page, because it earns one.
The order the returns arrive in
Two retirements can earn the same average return and end in completely different places, because the sequence matters. A bad first five years, while you are drawing income, does damage a good average later cannot undo. Under a smooth path our case survived every way we claimed it. Front-load the same returns with a bear market and the ranking of strategies flips and the plan nearly breaks.
Whether you can bend when you have to
Flexibility is worth real money. In the same case, one rule agreed to in advance, spend $6,000 less in the year after a bad market, lifted the stressed ending balance from about $166,000 to about $201,000. The rule was small. Deciding it before the bad year, rather than in the middle of one, is what made it work.
How the pieces interact
Claiming, spending, healthcare and taxes are not separate dials. The claiming age changes how much you must draw early, which changes your tax bill, which changes what is left to compound. A plan is a system, and the answer lives in the interactions.
This is why we never publish a “probability of success.” A single percentage buries the three things that produced it: what returns were assumed, what spending rule was used, and what counted as failure. Change any one and the percentage moves, while looking just as confident. We would rather show you the paths, the sensitivities, and the exact conditions that would flip the answer.