I've been struggling with this a bit myself. My answer is a 3 prong approach. Although due to this approach, I'm about 18 months out.

1) Over save. I'm planning to over save so that I can take a 20% hit without making a single spending adjustment. While this sounds like it could be a lot of extra working time, most of the over saving is driven by recent market gains. I'm only working the same amount of time that I would otherwise be with 0 returns over my last 2 years of work. If the market has losses in the next 18 months, then I'll adjust this 20% number lower.

2) Overweight bonds for the first 5 years. Assuming markets are still high when I've reached 20% over my total, I plan to start my retirement with a 60/40 stock/bond allocation. I will then move back to my desired AA of 80/20 over the 5 years by spending from the bond portion for these 5 years and rebalancing to higher stock allocations each year. (60/40, 65/35, 70/30, 75/25, 80/20) This is to help mitigate the sequence of returns risk of facing a large drop. (Larger than 20% of course) More info

here and

here.

3) Have a flexible withdrawal plan. I'm not actually planning to use a 4% WR or 3% WR or any static percent. I plan to adjust my spending based on market performance and portfolio balance, with a built in ceiling and floor. The ceiling is 4% of my original number, or what turns out to be 3.2% of the +20% over-saved number. The floor is

~~3%~~ 2.7% of my original number, or

~~2%~~ 2.3% of the +20% over-saved number. In addition, I don't plan to take any inflation adjustments for the first 5 years.

Is this too conservative? I don't know, but these current valuations have me nervous. If it turns out that there is no crash and the valuations resolve themselves by trending sideways for a while, then all the better.

(edited percentages in step 3, off initially due to bad spreadsheeting (rounding))