The .386, .50, and .618 retracement levels form the basic structure of Fibonacci grids found in popular market software packages, with .214 and .786 levels coming into play during periods of higher volatility.
Viewing the trends of the market through the lenses of a Fibonacci grid enables investors to see larger patterns beyond immediate upturns & downturns & to pinpoint prospects for profits that may be just beyond the view of investors who are spooked out by a short-term view of the trends.