You can set up a script that imports all data from the current copy of the file into the copy you deliver to them. This script can import from multiple tables and also update the next serial value settings of any fields that auto-enter serial numbers.
You can also minimize the need for such imports if you use the Convert to Seperation Model. With this approach, you have two files, one contains all layouts, scripts etc and a second contains all the data. With this structure, you can send clients a new interface file and they can just replace the old with the new and not need to import any data.