I was almost always disappointed with nannies and au pairs, it seemed as if you were adopting someone's child, rather than getting in somebody to help lighten the load. I would find a senior-ish citizen probably more useful as they can cook, and generally do not block the sink, the lou, or the washing machine, in other words they have more life skills. The best Nanny we ever had was in her late thirties when she started, and mid forties when she finished. The youngsters we had were just a trial of one's patience.