Who would use a metronome?

A metronome is a device that produces an audible beat—a click or other sound—at regular intervals that the user can set in beats per minute (BPM). Musicians use the device to practice playing to a regular pulse. Metronomes typically include synchronized visual motion (e.g., swinging pendulum or blinking lights).

Musicians practice with metronomes to improve their timing, especially the ability to stick to a tempo. Metronome practice helps internalize a clear sense of timing and tempo. Composers often use a metronome as a standard tempo reference and may play or sing their work to the metronome to derive beats per minute if they want to indicate that in a composition.

When interpreting emotion and other qualities in music, performers seldom play exactly on every beat. Typically, every beat of a musically expressive performance doesn't align exactly with each click of a metronome. This has led some musicians to criticize use of a metronome, because metronome time is different from Musical Time. Some go as far as to suggest that musicians shouldn't use metronomes at all, and have leveled criticism at metronome markings as well. See Criticism of metronome use.