Ducky,
I use to have concerns similar to yours. Especially while I was still working and approaching financial independence. My fear was that a correction would come along and push me back 5 to 10 years from retirement and I hated this thought.
As it turned out, I did wind up retiring after all without any delays. If I did not change my strategy and approach to all this, I would probably still have the same fears today.
My approach going forward now is to exclusively invest in Balanced Index funds.
In this fashion I know that I am selling high and buying low as time goes on. I feel no responsibility to tweak the system by making additional tactical changes in times such as this.
Some will say, "But Gauss - you can get a larger tax advantage by segregating your assets between bonds/stocks into after-tax and retirement accounts".
To this I say true, but it is not always about maximizing return. There is a robustness component to all of this.
Now that I have enough money for the rest of my life, I certainly don't want my emotions to come into it and jeopardize this.
Recall the quote attributed to Voltaire: "The Best is the Enemy of the Good". I think that it applies to my personal situation and helps me to sleep at night.
-gauss