Instead of constantly duplicating past contract templates, you can also save contracts as templates, and you can do that from your list of contracts.
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Just select 'Save as template' from the dropdown, enter a name for it that will help you identify it in the future, and voila...

Now, you can select it from the available templates the next time you create a new contract.  This will automatically fill in all past fields (except the client information, which is inherited from the project you're using).
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Note:  You cannot rename the templates or delete them for the time being. You can always create new templates reflecting your changes, though.