My small business has grown to a point where I either need to employ someone part time to do our admin & accounts or I'm going to wake up in a white jacket with very stylish wrap-around sleeves one morning. So now I've decided to employ another small business that offers exactly this service, to come in once a week to do all our admin & accounting.

What can go wrong with this? Bearing in mind that our business is probably 80% built on intellectual property, so obviously I would insist on an NDA, but what other precautions should I take?

I'd love to hear from anyone who has done this before, or even if you haven't, but are aware of the possible risks, whatever.