The worst thing a form can do is lose what someone typed. A dropped connection, an accidental refresh, a session timeout, and thirty fields of work are gone. Users don't forgive that twice.
The protections are straightforward: persist draft state locally as they type, make submits idempotent so a retry can't double-save, and warn before navigating away from a dirty form. None of it is exotic, all of it is rare.
For long government or intake forms, this isn't polish, it's the difference between a completed record and an abandoned one. The form's job is to protect the user's effort, not just collect it.
