How often does the moxa stick of moxibustion instrument change?

According to the inquiry of Apple Green Health Network, the time of changing moxa sticks by moxibustion instrument needs to be judged according to the power, and the use time of different powers is different. The high-power moxibustion instrument needs to be used for half an hour, and the low-power moxibustion instrument needs to be used for more than one hour.