Financial independence isn't about not working — it's about work becoming optional. The classic rule: a corpus of ~25× your annual spending can sustain you indefinitely at a ~4% withdrawal rate.
Returns, inflation, and your own spending will all differ from today's guesses. Recompute yearly. The point is to know whether you're roughly on a 15-year path or a 40-year one.
Going from saving 15% to 30% of income shortens the path far more reliably than chasing 2% extra return — and it simultaneously lowers the expenses your corpus must cover. It's the only variable fully under your control.
A crash early in retirement, while you're withdrawing, hurts far more than the same crash later. That's why early retirees use 30×+ and keep 2–3 years of expenses in debt — so they never sell equity in a drawdown.