Singers perform music (arias, recitatives, songs, etc.) that can be sung with or without accompaniment by musical instruments. Singing is often done in an ensemble of musicians, such as a choir of singers or a band of instrumentalists.
Singing can be formal or informal, arranged or improvised. It may be done as a form of religious devotion, as a hobby, as a source of pleasure, comfort, or ritual, as part of music education, or as a profession. Excellence in singing requires time, dedication, instruction, and regular practice. If practice is done on a regular basis then the sounds can become more clear and strong. Professional singers usually build their careers around one specific musical genre, such as classical or rock, although there are singers with crossover success (singing in more than one genre). They typically take voice training provided by voice teachers or vocal coaches throughout their careers.