My losers........2000 and 2001. I just held onto everything I had after the big run-up in 1999. The bubble burst, I held on. Then the election came, and "there's always an election rally", so I held on. Then we had the "hanging chad" and 36 days of "the unknown". It took 17 years for my account to get back to what it was worth in early March of 2000.
Ya, after that experience I was done with the "buy and hold" mentality. I time the market these days every time I see a change coming. I'm normally early on my predictions, so I forego some gains in the process. But these days I'm like Buffett........I'd rather have the cash sitting there waiting to reinvest rather than eeking out another 10% at a top. However, I do trade in my IRA's (Roth & Trad) on some of the big market moves I see. I did that this week, but when I do those kinds of trades, I generally don't hold a position overnight. I take the gain and move on.