Other Bluetooth LE devices like an AirTag can last beyond one year on a CR2032 battery, so consuming about 2 milli-watt-hours (mWh) per day.
An iPhone has at least 10 000 mWh battery capacity (depends on model), so in 1 month something like this consumes around 0.6 percentage points of battery.
An iPhone has at least 10 000 mWh battery capacity (depends on model), so in 1 month something like this consumes around 0.6 percentage points of battery.