Hi Larry, Most safety products require subscriptions that are $30 or more a month, however with invisaWear we don't charge any monthly fees or subscriptions. When we were initially designing invisaWear, the majority of people told our team that they have enough devices to charge and the last thing they want is for their safety device to be out of battery during an emergency because they forgot to charge it. That's why the invisaWear charm was designed to be non-rechargeable. Because the charm is very small and has a really compact design, the battery cannot be safely replaced without replacing the entire charm. The battery typically lasts one year but may last up to two years depending on usage. A replacement charm retails for $65 (almost like $5/month for your personal safety in comparison to typical safety devices which charge much higher). We hope this helps, if you have anymore questions, please don't hesitate to let us know.