unfortunately my red heat globes would only last a couple of weeks, however once i bought the ceramic one that has lasted a while, would have to be over a year i reckon. i do have a heat rock, but after a while i actually thought it had broken because it never felt that warm. it was still plugged in for ages though and now recently i touched it and was dumbfounded when i realised that it was still warm... i was never told from the pet store any dangers of heat rocks, which now especially after seeing that image of the diamond, im very disappointed about