Building on my prior post, to achieve financial independence, meaning being able to live off your accumulated assets without any other income, you need roughly 9,000 times your daily expenses.
The 4% “safe withdrawal rate” rule means that you can generally withdraw 4% of your investment portfolio per year, in perpetuity, without running out of money. This should not be taken as 100% assured, but is more likely to result in a much greater portfolio balance decades in the future rather than running out of money.
Based on the 4% guideline we can say that you need 25× your annual expenses, or 300× your monthly expenses, or 9,125× your daily expenses (rounded to 9,000× here for simplicity). The bulk of this money should be invested in equities, such as the Vanguard Total World Stock Market index fund. This could alternately be split between their U.S. fund and International fund for the same result with slightly lower fees, or restricted to U.S. stocks only if you want to bet on continued prosperity in the United States.
The 9,000× rule means that if your expenses are $100 per day, you need $900,000 invested to be financially independent. If you buy a $5 coffee everyday, you need $45,000 invested to sustain this habit in perpetuity. If you average $25 per day on food expenses (eating out, groceries, etc.), you need $225,000 just to account for this.
The 9,000× rule is more useful when looking at day-to-day recurring habitual expenses. If you smoke two packs of cigarettes per day at $6 per pack, you need $108,000 to cover this. (You may need extra money to account for increased health insurance premiums, reduced life expectancy, and worse health.)
If you are considering monthly bills, the 300× rule is simpler. If your rent is $1,200 per month, multiply by 300 to see that you need $360,000 invested to be financially independent with respect only to this expense.
The 9,000× rule can be quite useful for putting into perspective how much those “little” daily expenses are actually costing you. When Alex Trebek peddles whole life insurance as costing “less than 35¢ per day,” actually, the cost is closer to $3,150 with respect to financial independence, which is bleak indeed for an insurance policy that may have a maximum payout of $5,000 or less. A habit like dining out for lunch instead of packing a lunch could easily mean you need an extra $50,000 invested just to achieve financial independence. This is why there is such an emphasis on frugality in the financial independence / retire early (FIRE) community.