Pickup groups are formed to play in pit orchestras for musical theatre performances, operas, or operettas, accompany jazz singers or instrumental soloists, and act as a temporary backup band for a pop singer for a tour.
As well, pickup groups are hired to perform at social events such as weddings or holiday parties.
There are some disadvantages; using a pickup group requires contractors to pay for a series of rehearsals for the new musicians in each town, so that they can learn the songs/pieces.
As well, playing in these ensembles give local performers an opportunity to work with well-known national- or international-level touring soloists and conductors.
When a jazz singer or instrumental soloist, pop singer(s) or a rock musical production that is accompanied by a rock band, pop group or jazz group is on tour, they may hire a band of local musicians (e.g. a horn section or additional rhythm section members) in each town that they play in.
In some cases, the singer, soloist or production will have a core few musicians that travels with them, such as a piano player, who also acts as a bandleader (or a violin concertmaster for an orchestra) for the performances.