The Power of Compound Interest Learn how to harness the power of compound interest for your investments. Related Content 18 Years’ Worth of Days The average retirement lasts for 18 years, with many lasting even longer. Will you fill your post-retirement days with purpose? Retirement Questions That Have Nothing to Do With Money Things to consider before retirement. Keeping Good Records is Good Business Maintaining good records for your business not only helps to meet your tax and legal obligations, but it can save you money.