During set-up, the venue manager will check that the actual timeline is on schedule and will allow for the rehearsal. This is important to determine because rehearsals can get delayed or even cancelled if time runs out. It is the duty of the venue manager to ensure that a rehearsal does take place because it is their venue on show and nothing would be worse than a failure on stage in full view of the guests. If there is a band or entertainment, the rehearsal will allow for sound checks so that the production crew can adjust sound levels and microphone levels. The production crew will also set the lighting levels for the show and the lighting engineer will 'focus' the lights to create pattern or 'gobo' effects and illuminate particular spots. A rehearsal is not only for the benefit of people on the stage. It is an essential procedure for the production crew, stagehands, cameramen and backstage 'runners'.