I usually put it at $10M, and there are specific arguments for this.

The Trinity Study used a standard retirement portfolio and then studied its results using a sliding window starting from 1925. Let’s say you retire at 60 and expect to have another 20 years of life. This time period covers good stock market performance and bad, high inflation and low. It’s a very robust result, and the US and even worldwide economy would have to fundamentally change for it to be invalidated. (You could argue that Trump is driving things in that direction, but that’s a whole other discussion.)

How much of the portfolio can you withdraw each year and be safe?

The study starts with a percentage withdraw rate, which is increased by the rate of inflation each year. It then checks if the portfolio would have run out of money before the person is expected to die. This resulted in the 4% rule where you start withdrawing 4% the first year and then increase by inflation. It’s extremely unlikely that you’ll run out of money in a standard retirement period.

If you withdraw 3% or 2%, you won’t run out of money even if you live forever.

So let’s take a 2.5% withdraw rate. This is extremely conservative and should basically last forever. US government bond rates are typically higher than that (but not always), so we’re not even that tied to the stock market on this one. If you had $10M, take 2.5% the first year and increase by inflation each year after, you would perpetually have the purchasing power of $250k/year.

If you have $250k/year, you can live very comfortably anywhere on Earth. This is the part where someone always chimes in “what about the Bay area or New York?”

First, with this plan, you can live anywhere. You’re not tied to an area by a job. Maybe don’t chose high cost of living areas.

OK, let’s say there’s family or something else that’s specifically tying you to those areas. Median income in Manhattan is $106k, and the other burrows are significantly lower. San Fransisco median is $136k. I’m quite certain you can live comfortably on $250k in those areas if you absolutely had to for some reason.

Also, don’t forget that unlike all us working stiffs, you wouldn’t have to put another dime into a 401k or any other retirement plan. Your $10M already covers that. Feel free to spend it all on luxuries.

So that’s the limit. We can increase the $10M based on future inflation, but higher than that is just wanking about how much you have, and there’s no reason society should respect that.