WP All Import has in-depth support for scheduling recurring imports. You can specify how often you want WP All Import to check your feed for updates. When there are new items in the feed, WP All Import will add them to your site. When items are deleted from the feed, WP All Import can optionally delete their associated posts on your site. When item data is updated in the feed, WP All Import can optionally update posts on your site.

If your feed isn't hosted online, you can enjoy the same functionality by just uploading a new version of the feed using the "Re-import" feature.

http://www.wpallimport.com/how-it-works