If you need to export your order or shipment data over an extended period of time, ShipStation's Data Archive is your best bet!
At the end of every month, we create an archive of your account's orders, shipments, and shipment items, which you can easily download and open in Microsoft Excel or a similar spreadsheet program.
Getting to your Data Archive is easy!
Click Settings (the Wrench icon in the upper right).
Next, select Account Settings and then Subscription from the sidebar on the left.
Look for the "Data Archive" section near the bottom of this page, and then click the link in the description to view your month-by-month archives.
In this archive area, you can see the total value of your orders for a given month as well as that month's total shipping costs. Simply click Download Archive to download the archive for that month, which gives you CSVs of your order, shipment, and shipment line item info for that month, in a compressed file.