Sometime in the last 10 or 20 years, rock drumming has changed. Many drummers will now don headphones in the studio (and sometimes even for live performances) and synchronize their playing to an electronic metronome - the click track. This allows for easier digital editing of the recording. Since all of the measures are of equal duration, it is easy to move measures or phrases around without worry that the timing may be off. The click track has a down side - some say that songs recorded against a click track sound sterile, that the missing tempo deviations added life to a song.