Why does my savings rate determine how many years it takes to reach financial independence?

Your savings rate sets your timeline because it does two things at once: every dollar saved is a dollar you don't need to replace, and a high rate means you live on less, so your FIRE number is smaller. Income level barely matters by comparison. Roughly, saving 10% of take-home pay means working about 50 years; 25% drops it near 32; 50% gets you to financial independence in around 17 years; and 65% in roughly a decade — assuming you invest the savings at a real return near 5% and live off 4% afterward. The leverage is huge because raising your rate cuts spending and grows the pile simultaneously. That's why two people earning very different salaries can hit FI in the same number of years if their savings rates match. Track yours over time at wealthserene.com/tools/net-worth.