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 What Smart Investors Know Smart investors take the time to separate emotion from fact. The ABCs of Zero Coupon Bonds Understanding some basic concepts may help you assess whether zero-coupon bonds have a place in your portfolio. 5 Smart Investing Strategies Getting what you want out of your money may require the right game plan.