If you are using centers as the basis for your teaching, then yes, children will tire of them easily. I have had the same centers for at least 5 years and students still anticipate center day. They love the opportunity to experience what is often denied them. They love the how-to-draw books filled with horses, race cars, mythological creatures. They love the stamps, the art books, the mini etch-a-sketches. It amazes me that these simple things that I take for granted children view as a reward. :-)
K-12 Kansas Art Teacher
I can't imagine that the ideas of centers would be productive for an extended period of time.
Think of yourself, without instruction and ideas other than your own, how long would it take you, as an adult (with experience), to exhaust your own resources.
Isn't that the whole idea behind teachers, mentors and apprentices?
Isn't that why we have artednet? We run out of ideas and need instruction and inspiration.
Children need it all the more.