Contingency plans are needed in case of issues with locations, props, characters, lighting or costumes. Backup locations are needed if the primary locations become unavailable. Replacements for expensive props must be on hand in case of breakage. The filming schedule accounts for actor availability so scenes without a character can be shot if an actor is ill. All filming must finish before dusk since outdoor locations rely on natural lighting. Replacements for costumes are required in the event anything rips during filming.