If you invest in specific bonds, you will receive set interest payments at set frequencies until the bond matures. If you invest in a fund of bonds, you will receive payments (which you should automatically reinvest) based on the average yield of all of the bonds that the fund owns. That figure changes over time, and at any particular time, you can find the current yield. You can find this figure in the fund’s prospectus, and it is available when you look up the ticker on free services such as Google Finance or Yahoo Finance. To find out what sort of bonds a fund holds and how they will allocate future contributions, you will need to download the prospectus and read it.