I agree completely with Sdrummer. I shoot always in RAW, save them to an external HD. Then after PP´ing, another save. There are many programs out there which convert them quickly to JPG-format if you need it for e-mail etc., where large files are unwanted
Also, if you want to change the photo ( I mean pp´ing differently, another look), take the old RAW-file because all the information is retained.
In contrary to JPG-files.
Although RAW-files take much memory, I haven´t been so far that my card was full so that I had to copy the pics to my laptop before continuing. And I take often pics at fps-mode (sports)