Metronome is a device that musicians often use so as to keep a track of the measures and beats. A metronome marks time at a selected rate and gives a regular tick sound which allows the musicians to sing or to play their instruments in rhythm.
Commonly, guitar players make use of the metronome to learn about rhythm and strumming along the rhythm. Without having a proper rhythm in music, any musical piece whether vocals or instruments won’t sound good at all. Hence, it is important for musicians to make use of the metronome while recording or while they are practicing.