Federal CSRS and FERS retirement benefits are generous and you will have to select what you want to keep and at what level prior to leaving. You can't increase your coverage after retiring and there are many benefits to consider. It is beneficial to look at all options before deciding what is best for you and your family. You also need to read the fine print as they say. In other words, read the retirement forms front to back to fully comprehend and understand what your options are.