generally you can e-file five returns using the same machine --- that is IRS dictum. You can move to a different machine, install . prepare and file up to five more. I am not sure but TurboTax may prefer that you buy another CD and install on a different machine.
Note though that per the software agreement , you cannot charge for any returns you prepare ( for family or otherwise) -- this is not a business product. For preparing as a professional , Intuit offers Lacerte, ProSeries etc.
