Do people have to fill out form in one sitting? i.e.., can they work on it over a period of a few day?

Hello bill4jc,

Yes it is possible to achieve your requirement. It is possible to save the input data and continue later. There are two options available to achieve this:

#1. Save form input data in session: This feature allows the form input data in session and that is stored on server. This feature actually requires two forms where the main form should have the "Page Break" field. The data is only saved in session on the click of the next button. The following guide should help you:  http://www.jotform.com/features/save-and-continue/ 

#2. Auto Fill:  Enabling the "Auto Fill" feature of form will save the input data in browser cookie. Please be noted that if the user access the form again from any other browser, other system or clear the browser cache, the saved data will not be accessible anymore. The following guide should help you:  http://www.jotform.com/help/227-How-to-Enable-Auto-Fill-Feature-Save-Form-Entries-to-Continue-Later 

Hope this helps.

Do get back to us if you have any questions.

Thank you!