The key is to not twist them off, geez like we didnt know that! But to often i have seen people get frustrated and just lean on bolts till they break! I have found that if you are taking old bolts out , to soak them with penetrating oil and to turn them out until you feel some resistance, like just before the head snaps off.Stop and slowly turn it back in 1/4 turn, and then alternate directions using some more oil. By repeating this 1/4 out, 3/8 out it will USUALLY co-operate with you. Just something i have learned over the years. hope this helps