If you've put a few hours on it and all is well (look up bathtub curve), I can't imagine you'd need anything other than spare batteries and the spare props. Unless you 'prang' it, I'd see no reason why it would fail, and if you do have a big accident, I doubt you'll have enough spares. To be certain, take another Phantom...
Do take several memory cards, and something to download them on to.