Treatment duration after accident: ① mild whiplash/contusion: 2–4 weeks, ② moderate (multiple injuries): 4–8 weeks, ③ severe (with bone fracture, herniated disc): 2–3 months or longer, ④ chronic sequelae prevention: additional 1–2 months. Auto insurance covers reasonable duration based on injury severity. Most patients recover fully but neglected injuries can become chronic. Continue treatment until full functional recovery, not just pain relief.