In a research report Deutsche Bank recently said the following:
"The next decade will likely be one where buy and hold will generally be a fairly poor option in developed markets," Deutsche Bank analysts write in a letter to clients, MarketWatch reports."
It would have been great, and saved investors a ton of money, if they figured this out last decade.
Buy and hold is always a bad option. During market upturns it appears to work well along with everything else (monkeys throwing darts at the Wall Street Journal, astrology, palm reading, etc) but the market doesn't go up forever and it makes no sense to ride it all the way down.