An annuity may seem like a great idea for a worry-free retirement. After all, you give a company some money, and you get a stream of guaranteed income for the rest of your life, starting either right away (immediate annuity) or at some point in the future (deferred annuity). This can certainly give retirees peace of mind, especially when compared to a stock and bond portfolio that can fluctuate in value significantly over time.However, there are a few things you need to know about annuities before you consider one.First, annuities are notorious for having high commissions and fees.