2004 Buick Rendezvous barrings

My 2004 buik rendezvous has a problem I think. I have replaced the barrings twice now since I have owned it. It is at about 95 thousand miles now, and I baught it when it was at 30 thousand miles. It kind of makes a grinding sound when I stop sometimes. I have replaced the brake pads. Even know they where not bad. It sounds like a boat after so long when you are driving on the highway. That is how I know the barrings are going out. So this will be the third time I will have to replace a barring since I have owned the vehicle. I know more then a average woman about fixing a vehicle. My dad taught me a lot as a kid. I know how to replace a lot of things without taking it to the shop. But this barring problem has not ever came up in my life. I guess my question is what could be causing my barrings to go out so frequentally? I might be good with cars, but not that good. So PLEASE help me with some good advice. Thank you and have a great day.