When you open your sensor to install or replace the batteries, you will notice a toggle labelled LT/RT. This toggle is here to let you balance sensor reactivity and battery life.
"LT" stands for "Priority to Life Time". "RT" stands for "Priority to Response time".
In both cases, the sensor will report "motion" to the lights immediately when motion is detected after a period of inactivity.
However, in LT mode, the sensor will only send the "no motion" message 12 minutes after the motion has stopped. This will extend the lifetime of the batteries to 2 years.
In RT mode, the sensor will send the "no motion" message 5 minutes after motion has stopped, but batteries may need to be replaced more frequently.