So far as I've seen there's no way you can actually guarantee the chain won't break. You can make it absurdly unlikely to break, but it's still possible.
I think that if you are careful enough, that chance is close to negligible. I've chained, like, a hundred and a half times, but only broken chains without doing anything wrong about five times, and I recently learned that I may have been doing something wrong all along (which I fixed). So...