Before you invest--1. Make sure you understand call provisions. When can the issue be called and at what price?2. Be very careful of issues priced over their call price. With interest rates very low, many of the quality issues sell at a substantial premium. Hence, the issue can be called from you at a loss.3. Check those bond ratings. The high yield issues often have junk bond ratings.4. Diversification allows you to tolerate a bit more risk, but there are limits. Don't over do the high yield stuff unless you can afford the loss.