<prompt> Human: Ive been reading lately the common advice on investing; invest early and often, dont try to time the market, just leave it and forget it. At the same time, in 2008, a lot of investors had their savings completely wiped out; some by fraud or terrible banking practices, some by having the company they held their investments in close down.What were they doing wrong, and how can one avoid hitting the same issue in the future? If its company fraud, do you just invest through multiple companies and hope that at most only one of them goes belly-up? Was it only the investors who were in derivatives trading who got hit, and stock market investors get away with only the declines of the market? Id really like to understand what those investors missed, or how they couldve sheltered themselves.  <response>: They sold. Buying high selling low is a great way to destroy your portfolio. 