Real investment risk is measured not by the percent that a stock may decline in price in relation to the general market in a given period, but by the danger of a loss of quality and earnings power through economic changes or deterioration in management.
Benjamin GrahamNo matter how careful you are, the one risk no investor can ever eliminate is the risk of being wrong. Only by insisting on what Graham called the "margin of safety" - never overpaying, no matter how exciting an investment seems to be - can you minimize your odds of error.
Benjamin GrahamMost businesses change in character and quality over the years, sometimes for the better, perhaps more often for the worse. The investor need not watch his companies' performance like a hawk; but he should give it a good, hard look from time to time.
Benjamin Graham