How many years until you never have to work again?
Your FIRE (Financial Independence, Retire Early) number is typically 25× your annual spending. Based on the 4% safe withdrawal rate from the Trinity Study, this amount would sustain your lifestyle indefinitely in most historical scenarios.
The 4% rule says you can withdraw 4% of your portfolio in year one of retirement, then adjust for inflation each year, and historically your money would last 30+ years in ~95% of scenarios. For early retirees, many use 3.5% for extra safety.
Lean FIRE: covering only essential expenses (~$40K/yr spending → $1M target). Regular FIRE: comfortable lifestyle (~$60K/yr → $1.5M). Fat FIRE: luxury lifestyle ($100K+/yr → $2.5M+). The distinction helps set realistic targets.
Savings rate has a dramatic, non-linear effect. At 10% savings rate → ~40 years to FIRE. At 25% → ~32 years. At 50% → ~17 years. At 75% → ~7 years. Each percentage point matters more as you go higher.
Coast FIRE means you've saved enough that compound growth alone will grow your portfolio to your FIRE number by retirement age — you no longer need to save, just cover current expenses. It's a popular milestone on the path to full FIRE.
FIRE is achievable for many middle-income earners with discipline. The median FIRE achiever earns $80-120K/yr. Key factors: savings rate (aim for 50%+), low-cost index fund investing, avoiding lifestyle inflation, and understanding that FIRE doesn't mean 'never work again' — it means work becomes optional.