What is the average lifespan of a defib or battery?

That varies depending on the defib. We always ensure a timely on-site defib exchange. When your defib is due for maintenance, it will be exchanged at your premises for a defib that has just had a maintenance service. This ensures your defib is 100% ready for use for the next 2 years. Maintenance is also required after deployment or when the defib beeps (indicating a malfunction during self-tests), and we always resolve this with an onsite exchange of the entire defib.