The first time you changed your bearings, how many miles/Km did you have on them? How often are you suposed to change them?
I installed my Rotora Front Sloted rotors last week; to get the captive disc out, they had to take to change the bearings, and one went broke, so I had them both changed at 49K Kilometers. But it seemed as they had still a long way to go...

 

I bought my car with about 94,000 kms on it. almost 60,000 miles It was kinda old. I had to replace my driver side rear right away. Then my pass. side rear and driver side front after a trip out west.

guess this one was definitely due to go. It lasted a long tiime though.