What Smart Investors Know Smart investors take the time to separate emotion from fact. Share | Related Content 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. What’s Your Investment IQ? You make decisions for your portfolio, but how much do you really know about the products you buy? Try this quiz Impact of Taxes and Inflation Estimate the potential impact taxes and inflation can have on the purchasing power of an investment.