Note that looks like you are assuming 4% investments after retirement. Per the passive investment chart, this implies a fairly high level of risk? I'm unclear if you're also assuming we will live forever?
* It is looking at a 30 year time horizon. For longer periods you'd need a but more money, but not double. 3% is incredibly safe, and wouldn't take that much longer to acquire once you're at 4%.
* Slight reductions in expenses during down years have a huge effect on the overall success of the portfolio. If you could reduce expenses to 3.5% during severely down years, that would significantly help the success and longevity of your portfolio.
