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 Should You Invest in Exchange Traded Funds? There are hundreds of ETFs available. Should you invest in them? Asset Allocation Consider how your assets are allocated and if that allocation is consistent with your time frame and risk tolerance. 5 Smart Investing Principles Principles that can help create a portfolio designed to pursue investment goals.