Another rule of thumb......prior to take off...note hover power while into wind....depart and hold that power setting.....determine the airspeed that provides a 500 FPM ROC.
Prior to landing....adjust power to achieve the same airspeed as determined at takeoff and note the power required.....then pull power to achieve the 500 FPM ROC and note the poorer required.
Ensure the pre-landingCheck is done in calm air.....and not in up-rising air!
This gets you to thinking about power management at both ends of the trip and is a measure of power available at both ends of the trip.