or hire a "pick-up group" in each city or country. There are advantages and disadvantages to each approach. Using a longstanding ensemble will provide a group which has extensive experience performing as a musical ensemble. This can help the group to play with a more unified sound and style. If the backing band or backing ensemble required for a show is small (e.g., 3-4 musicians), it may be worth the cost of paying for the travel, hotel and food for a longstanding group. However, if the backing ensemble is large–for example, a 20-piece big band for a jazz singer or a 27-member pit orchestra for a travelling musical, the cost of travel, hotels and meals for the backup group may be prohibitive. Alternatively, in each town or city, the producer or promoter can pay a local music contractor to hire a local musicians to form a "pickup" orchestra or a "jobbing band". If a promoter decides to hire a pickup group in each town or city, this means that the promoter does not have to pay for the travel, hotels and meals for these musicians, since they live in the town or city where the show is taking place. 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, since the pickup group will not have experience playing together and since they may not have experience performing the songs/pieces in the show, a pickup group may not play with the same "tight" ensemble as a longstanding group which backs up a soloist or musical theatre/opera company on a permanent basis. As occupation Although the work provided by these ensembles is intermittent and of short duration, these ensembles are an important source of income for freelance musicians and session musicians. Since playing in "jobbing bands" and "pickup groups" only provides a limited amount of work per year, a performer that plays in these types of groups will typically have to have other sources of income, such as teaching music on her instrument. As well, playing in these ensembles give local performers an opportunity to work with well-known national- or international-level touring soloists and conductors. Orchestras When a musical theater production, operetta, or opera is performed in different cities, the production company may hire local musicians in each town