> So there's some minimum income that everyone needs (and it's different between people) where they can "forget" about living expenses and still have a relatively stress-free life. I'd wager somewhere around 1.5x - 2x the cost of living.

I take into account volatility of future income in order to be stress free. Hence my goal was to own businesses where my labor wasn’t needed to keep the income flowing in case I get injured.

Dual income household where each person earns enough to cover expenses can serve a similar purpose.