The more they do the more they are likely to have fault. At least your current horse is willing to do it, so she isn't that bad.
Look at mine! she isn't even assigned the least thing to do simply because she is totally unreliable.. How can I find any major faults of her?!
Yes, you are right !! No matter how good they are, we still need to keep watching or else the lil kids will be the one to suffer. Partiularly your have two young aged kids at home and you are out at work most of the time.
Your twins babies are so lucky to have you who is so cautious about every tiny little stuff of them.