Battery life on sensors

Recently joined the Smartthings community so still learning.
How long can I expect the batteries to last in the Multi sensor, and the door sensor ?
Installed both 5 days ago, and both showing 50% life. However not sure how much was in to start.
What can I expect .

Dont worry about the reporting as its more like a 4 position not absolute. So 50% could mean anything from like 75 to 30% …we just dont know. Most my st multi sensors last anywhere from 6 months to 18 months depending on how active they are. Most are closer to 12 months than anything.

The problem with battery not-not-included devices is that you don’t get to pick the battery, and sometimes the batteries that ship in the box are not the best.

The battery life estimate is usually derived from the voltage, with a calibration curve used to translate from volts to percentage remaining. Both the voltage measurement and calibration curves are coarse grained.

You can get a better idea on whether your batteries are any good by using a cheap multimeter to check the voltage.

If the nominal voltage is 3.0V, but they start out at 2.8V, they may not last as long as you may hope. They may still show as 100% in the device when you first put them in.