Are Animator components expensive?

In terms of having a lot of them in the scene at once?

Specifically, animating all the different sprites you'd have in a 2D game. Projectiles, scenery details like grass, water, etc. That can all add up and I was wondering if having an Animator component on all those game objects would have a huge impact on performance. I seen that 5.2 will have a new feature for animating sprites but that's still a ways off. What is usually the best method for animating an abundance of 2D objects?