The estimated battery life is up to 10 years under normal usage. Of course, extreme usage and conditions may affect this.
Here are 3 tips to help you achieve a 10 year battery lifetime:
1) Make sure you have a stable Z-Wave network; this means that you always get one single confirmation blink that shows that your Strips is acknowledged by the gateway.
2) Ideally, you should have a direct connection between your Strips sensor and your gateway to have a battery lifetime of 10 years. When we have made the battery lifetime estimation we have taken into account the usage of extenders in your Z-Wave network, however you need to be aware that the higher the number of extenders, the higher the effect on the overall battery lifetime of Strips.
3) Configure Strips: make sure that the wake-up time is set to 24 hours and polling is turned off.