This wasn't my first market panic as an investor, but it was my first since FIRE. It has not phased us, and our NW is now higher than before. Not really due to any skill on our part, but rather having a good set of investment principles and sticking to them. First and foremost: Don't invest short-term funds in long-term assets.
For example, we sold off some real estate several years ago and promptly plowed most of the proceeds into aggressive long-term investments. However, this January we modified our plan to relocate out of California into a RE market that was, and still is, very hot. We decided it would be best to make an all cash offer, and to do so before our current residence went on the market. To do this we needed more short-term funds in reserve, so in February we reallocated a large sum from aggressive investments to something very conservative. Thus we accidentally timed the market by sticking to our investment principles.
Later, after everything hit the fan, this wasn't an issue at all for us or even stressful. Of course, I don't like seeing our portfolio drop, but we knew it would eventually recover. And we didn't stress because we maintain a fat emergency fund. Again, this is based on the idea that you shouldn't keep short-term money in long-term investments. Money we need to live for the next 1-2 years is short-term, so we keep a chunk of our portfolio in something more conservative. This deviates from conventional wisdom around here, and I know it's less "efficient" but I don't care :) Sleep and happiness are more important than earning an extra 1%.
After we relocated and sold our former dwelling, we had a chuck of change laying around that we needed to do something with. This was early July when COVID cases were on the rise and the media was pounding the fear mongering drumbeat again. This was difficult to do, but we lump summed it all in the market because we had more than sufficient emergency funds and so this was all designated long-term. Within a couple of weeks it returned enough to more than offset the cost of relocating. Lesson relearned: The media is entirely useless in prognosticating the future (among other things), and investment media in particular is worse than useless as it's all a bunch of charlatans with competing axes to grind.
Not of this is really new information for me, but useful affirmation of our general strategy. And a good reminder to ignore the talking heads, turn off the dang news feed, and enjoy life in the real world more.