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 The Junk Drawer Approach to Investing It's easy to let investments accumulate like old receipts in a junk drawer. 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 5 Smart Investing Principles Principles that can help create a portfolio designed to pursue investment goals.