Having a showreel will greatly enhance your career as an actor. Your showreel should be comprised of pieces of work from your career and should showcase your versatility and flexibility as an actor. Nowadays most casting professionals and agents won’t even consider seeing an actor without seeing a showreel first.
For most performers, it’s your foot in the door, your first step, but most importantly it’s something that will help you get your next job. As your showreel builds, so will your career.