Savings rate dominates income level
The percentage of gross income saved to investments determines retirement timing far more than the absolute dollar amount earned. A 50% saver retires in roughly 17 years regardless of whether they earn $50k or $500k per year.
This counterintuitive result emerges from compound math: high savings rate means more principal compounding, and the time for assets to grow depends on that growth rate and how much of income is deployed, not on total income itself.
The steep curve at extremes
Below 10% savings, retirement takes over 50 years. By 25%, it drops to 32 years. At 50%, it hits 17. Above 75%, the target shrinks below a decade. The curve accelerates because each percentage point of savings buys more compounding time, and at high savings rates, the required portfolio is smaller relative to spending.
The practical implication is that lifestyle optimization and expense reduction matter more than earning increases for retirement speed.