My experience has been this...when I set it up it stays there...BUT it works like object collsion in the assembly room. If your hit the limit it stops...if you keep yanking on it it ignores the limit. I animated a robot once. I really like the feature b/c sometimes you want to go past the limit in certin moves (ie: sometimes whats correct and what looks right is not the same) but then you do have to reset. As for losing constraints after a save/reboot cycle..it never was a problem for me. Sometimes I have lost 1 constraint but never a whole skeleton of constraints..... -brent