I love our nanny to bits and (more importantly) the kids love her, and she's great with them, so I'm not sure if IABU and should just accept this.
Basically, I've found that the house is more likely to get dirtier and things get damaged when the nanny is looking after the kids, as opposed to when I'm looking after them. By dirtier, I mean that she continuously allows the kids to have messy food (bowls of pasta and ice cream) in the sitting room on the fabric sofa despite me asking her not to. Also, she allows them to take the cushions off the sofa and jump on them to the point that they are all stained.
Along with this, I've discovered that under her watch, one of the kids scribbled felt tip all over the kitchen table legs which are white, and this won't wash off. Ditto to paint on the table top that has left a permanent stain. There are more things that I can think of but this is just a small example.
To be clear, she doesn't clean for us as we have 4 kids and I feel that she has enough to be doing.
I don't know if IABU or not, obviously I know that someone coming in from the outside is not going to stick to the high standards I have for my own home, and I also know that things like this have also happened under my watch, though not as frequently.
Should I just accept this as one of the downsides of having a nanny?