What is lean FIRE vs fat FIRE?

Lean FIRE targets retiring on a very modest budget — typically $25,000 to $40,000 per year — requiring a smaller portfolio (around $625,000 to $1,000,000 at a 4% withdrawal rate). Fat FIRE targets a more comfortable lifestyle — $100,000+ per year in retirement — requiring $2,500,000 or more. Most people aim for somewhere in between. Your target depends entirely on your desired retirement spending.