First lets look at back teeth that break or crack. Often the teeth that break have fillings that undermine the existing tooth structure. Even a small filling placed close to the edge ( the mesial or distal of the tooth) can make a crack more likely to develop. Many of these teeth really should have onlays or crowns placed to protect them.
Another factor is the occlusion and frequency of night time clenching and bruxism ( many people do this at times while sleeping). Patients that have worn their teeth flatter so that there posterior tooth surfaces meet quite broadly during excursions often apply more force to their posterior teeth. These are people who have "cow bites" (Dentists term). Often when I examine these peoples teeth they have multiple posterior broad wear facets from their forceful grinding and chewing.
Destructive habits , such as chewing on ice cubes, bones and other hard substances can also cause teeth to break. I had one teenaged patient who had no fillings in her teeth but kept breaking her teeth. It turned out she had a habit of chewing on to a pen top (kids do the darnedest things!)
I have also observed that older patients, whose pulps have receded (no pulps in their clinical crowns) seem to be more likely to experience tooth fracture. This is especially true if the have a deep overbite involving their anterior teeth.
Some dentists advocate changing the occlusion of patients by extensive tooth equilibration or by reconstructive dentistry. My solution is simpler. For most of these situations is to recommend that my patients wear a nightguard while sleeping that will protect their teeth and help eliminate destructive tooth to tooth contacts at night. This seems to be the least invasive choice and to my mind it is a "DO NO HARM" solution to the problem.