If you forget to bring your NHI card with you, you are able to visit a doctor by paying a deposit and then get refunded within ten days (excluding holidays). Under unexpected circumstances, such as natural disaster, cross-city medical visits, card damage or loss, you may still get a refund from NHIA within six months.
In addition, the NHI APP is highly recommended. If you have a registered virtual NHI card, you can go to the participating hospitals/clinics and scan the QR Code instead of using a physical NHI card.