What Does Working Five More Years Really Buy?

“One more year” can become a habit. The financial benefit of working longer is real, but it helps to put a number next to the years being exchanged. Consider a deliberately simplified choice: retire now or work five more years. Assume $10 million in investable assets, annual household spending of $300,000, an additional $150,000 saved at the end of each working year, and a constant 7% annual investment return. These are hypothetical inputs, not a forecast.

At the end of year five	Simplified portfolio value
Retire now and withdraw $300,000 at each year-end	About $12.30 million
Keep working and add $150,000 at each year-end	About $14.89 million

The difference is about $2.59 million. It has two parts: roughly $1.73 million from withdrawals avoided, including their foregone growth, and roughly $0.86 million from new contributions and their growth. The $10 million starting portfolio is in both cases; its growth cancels out when comparing the two paths. Starting with $20 million under the same assumptions gives the same dollar difference, though a smaller percentage difference. The arithmetic is less mysterious than it may feel.

The model leaves out the decisions that matter most

Real markets do not return exactly 7% each year. A sharp loss early in retirement changes the result because withdrawals then sell more shares at low prices. Inflation, taxes, healthcare premiums, and account withdrawal rules also affect the amount left to invest. The $150,000 contribution must be after all taxes and work-related costs. Home equity should not be counted as investable assets unless there is a credible plan to access it.

The comparison also has a nonfinancial side. Five more working years may provide purpose, colleagues, and health coverage. They may also consume the healthiest years available for travel, family, or work of a different kind. A spreadsheet can put a price on the additional savings; it cannot tell a household how much those five years are worth.

Use the calculation as a sensitivity test. Change the spending amount, savings, return sequence, retirement date, and expected income from Social Security or a pension. The Social Security Administration’s estimate tool helps with one of those inputs. If the decision reverses after a modest change in assumptions, the plan needs more resilience before the calendar decides for you.