The Rule of 72 Do you know how long it may take for your investments to double in value? The Rule of 72 is a quick way to figure it out. Share | Related Content It Was the Best of Times, It Was the Worst of Times All about how missing the best market days (or the worst!) might affect your portfolio. The Utility of Sector Investing Successful sector investing is dependent upon an accurate analysis about when to rotate in and out. 5 Smart Investing Principles Principles that can help create a portfolio designed to pursue investment goals.