I was going to purchase a rebuilt unit from O'Reillys. I'm replacing it because a boot went bad and now the axle needs to be replaced. The answer to why only do the one side is 1) the other sides boots look ok and 2) lack of funds to do both right now. I bought this car about 3 years ago for my sons to drive and so far it has been driven on average 1200 miles per year. The axles from O'Reillys is only $120 what are they elsewhere?