Daily life stresses, kids, spouses, etc cause us to grind our teeth. Cracks are like potato chips, you can never have just one. Afterall, to crack one tooth you must be chewing against another tooth. Stop your grinding and clenching, and get a bite guard. You must soften your diet.
Gum chewing, raw carrot stick eating, bagels, pretzels, ice, etc, etc, etc, cause cracks in teeth.
The manufacturers would lose money and pull ads from the television stations. Don't alternate from hot to cold foods. I had a root canal about 10 years ago and in May I got a massive abcess and lost that tooth. I went back last week to start work on the bridge to replace the tooth and 3 days later, the tooth next to the one I lost started to hurt. Today, I'm in tons of pain much like the first abcess.