How (and Why) to Build a House Book
51 minutes ago
I agree that wealth should be measured in units of time rather than dollars -- as in how long you can holdout without any wage income. But the correct denominator is annual expenses, not annual income. You're ready to retire when your networth divided by your annual expenses reaches 100 minus your age in years.
Investing well increases the numerator, but even investing badly still shrinks the denominator (assuming you don't borrow to invest). I think a conservative target number [for this quotient] is 100 minus your age in years. This way there's little chance of outliving your money.