Can I add the ability for users to 'save' their form so they can complete it later?

Hi,

To allow users to submit the form and then return at a later date to complete the rest, you can setup and autoresponder with an edit submission link:

http://www.jotform.com/help/26-Creating-a-Form-Autoresponder

http://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date

This will give the user filling out the form a link to return to their specific submission and update the form data.