A stockbroker was selling a stock to Mr. Jones, a client. "I think this one will really move," said the broker, "it's only $1 a share."
"Buy me 1,000 shares," said Jones. The next day the stock was at $2.
Mr. Jones called the broker and said, "You were right! Buy me 5000 more shares." The next day Mr. Jones looked in the paper and the stock was at $4.
Mr. Jones ran to the phone and called the broker. "Buy me 10,000 more shares," said Mr. Jones. "Great," said the broker.
The next day when Mr. Jones looked in the paper the stock was at $9. Seeing what a great profit he had in just a few days, he phoned and told the broker, "Sell all my shares."
The broker said, "To whom? You were the only one buying that stock."
http://blogs.forbes.com/greatspeculations/2010/07/02/buy-and-hold-is-dead-and-gone/
“Proof of the fallacy of buy-and-hold as a strategy is easy enough to find. In the 1929 crash and its aftermath the market lost 86% of its value and did not get back to its 1929 level until 1955, twenty-six years later. That was 26 years of waiting for buy and hold investors (if there still were any) for the market to ‘come back’.