"keep it simple" is not easy to have. we need to forcast before to valuate. to forcast is a complex anaysis of competition and requires experience to so. valuation need to be quick and good at number.

forcasting is process of realizing future in long term. a strategic point of view is required. we need assumption about customer demand and competition in the future , which could be different from the past, to make a future earning of the firm. this required experience