Change is crucial! It helps elevate the level of an actor's inguenity on stage. Playing the same type of roles repeatively has it's place, but it can also stunt your growth as a performer. It's just too easy to get relaxed in roles that don't challenge you. Actors should pursue roles that force them to dig deeper emotionally, challenge them to excel in voice manipulation, and give them stretch in the areas of aggression with characters that have no boundaries and make no excuses. That is where real acting begins. As you seek to polish your craft of acting, go after roles that stretch your imagination, pull at your comfort zone, push you to excel vocally and physically, and will give the audience an opportunity to see you in multi-faceted dimensions. Keep in mind that you are an actor, not a mainstay prop.