Ceramic pan overheating damage How can you tell if a ceramic non-stick pan has suffered damage from overheating?

Will there be a point at which the pan is no longer safe to use? If so how can you tell if this is the case?
The main issue you will see with ceramic pans is crazing (a network of small cracks) of the enamel layer from  thermal expansion and contraction.

This may reduce the non-stick properties of the enamel layer and is not terribly attractive, but otherwise the pan will continue to be usable.