It is difficult to exactly pinpoint the required rate of return due to the various estimates and preferences that differ from one decision maker to another.The various factors that determine the rate of return are the risk return preferences, inflation and the capital structure of the firm. Each of these factors greatly affect the intrinsic value of the asset. It requires lot of experience and practice to determine the perfect rate of return,that makes the investment decisions more predictable in the future. The bottom line is to refine your preferences and estimates for any investment to get a good rate of return.