I think it depends very much on their ability as an actor. Do they have the versatility they need to move easily into another role, or do they allow themselves to become trapped in that character? After playing a particular character for so many years, I suppose it would be easy to become trapped in that role, but I know Emma Watson filmed different things while also filming Harry Potter such as Ballet Shoes. I think that certainly helps to break out of a character by doing different roles to show that you're not just good at one particular type of character. Type casting is very common, and I don't think I would want to be cast into the same kind of role over and over again just because I played that type of role for seven or eight years. And sometimes, maybe the actor has to go out of their own way to do an independent production to show that they can do other roles, too if that's what they want. I think actors have a choice in it to an extent. (This coming from someone who knows a few actors and even the dance world where you can get cast as the same type of role over and over and never get much different... think Nina from Black Swan if you want a reference).
Shiloh Adlar, Sixth Year, Prefect, RQT Co-Captain"Let us read, and let us dance; these two amusements will never do any harm to the world." -Voltaire