moogal-- I also sometimes see wrists and ankles breaking, but it's usually when I have too many body parts set on IK at once. Lately I've been doing IK in a stepwise fashion. For example, to do a feet-planted dance, I'll turn IK on for the feet then animate. Go to the animation pallette and erase the keyframes for toes through thighs. Then turn IK off for the legs and turn it on for the hands. Run the animation, then erase the keyframes for the hands through collar. Then turn off IK for the hands. Turn it back on for the feet and again erase the toe through thigh keyframes. When I then run the animation with IK on for the feet, things move reasonably naturally (i.e., feet are firmly planted, hands move slightly but stay close to same place, and nothing breaks or twists badly) ... all without turning on limits. A bit tedious, though, until you get the hang of the sequence; and maybe someone has a better technique.