They crack because the user heats them up too fast. I start my BGE with a very small fire to let it slowly warm up. I've had mine peg the needle off the scale (by accident) and not crack. I'm on my 7th year with this one.
Well, story time. I lit my egg one time and waited a bit to go check. I was trying to get to 350. It was showing 200. I said that’s not possible. It’s been too long. I tried to lift the lid (thank goodness it didn’t open, at least not easily). The thermometer had spun all the way around and went back to 200. It didn’t open because the seal had melted together. A few days later I used a knife and a saw and got it to open. I replaced the seal and it’s doing fine no cracks. It’s only 10 years old though.
