This thread is interesting.
It's made me realize that my understanding of the 4% rule was flawed. It never occurred to me that I could continue withdrawing 4% of the starting value of my portfolio every year, no matter what happened, i.e. retire with $1M, withdraw $40,000 the first year, in year two portfolio value drops 40% to $600,000, still withdraw $40K... My understanding now is that, historically, most times, even if I did that, probably my nest egg would survive for 30 years.
To me, that seems like pretty reckless behavior, and I have no intention of doing that, but it's nice to know that even if I did, probably I wouldn't run out of money.
My wife and I are planning on being flexible and definitely reducing withdrawals, probably down to just dividends, from our stash during serious downturns in the stock market, and getting at least part time jobs doing something low stress and relatively enjoyable (because we know it's just temporary). When stocks go on sale during market crashes, we're planning on making enough money to at least max out our IRAs for a year or two, so that we can buy shares at a discount. Conversely, as our stash grows, I won't have any fear about spending 5% or even more, some years, because I'll know that when the markets head south, I'll be ready and able to reduce expenses accordingly, either by working and/or using geographic arbitrage and moving to a lower COL part of the country/world.