Most aircraft have a section in the SOPM that states something like "At nn feet Radio Altitude, reduce power to Idle." Certainly, the five aircraft I have on my licence all insist power is brought to idle; the height varying from 50' to 30'. But be very wary of hot shots telling you to leave power on if the manual states otherwise. I've flown with some of these plonkers and gobbled up runway like it's going out of fashion. As ever though, your manual will state the appropriate technique.
PM