If you subscribe to one of our 24/7 monitored personal alarm services then one of the SureSafe team will let you know either if your elderly alarm bracelet or pendant needs charging, or if the battery or pendant needs replacing (depending on the type of alarm you have). If it is the latter, we will send you out a replacement free of charge. If you have a family monitored alarm then you will receive a text alert to let you know, or LEDs on the pendant or wristband will indicate a low battery (depending on the type of alarm). With the Guardian you will get in-App alerts as well as email alerts when you need to replace the battery. The LCD screen on the base unit will also tell you.