Photographers: 2 or just one?

I'm very torn between having just one or two wedding photographers. We've found a few photographers for ~8 hours at $2500. However, you can add a second photographer- but that price increases quite a bit. Is it worth it to have two?

Maybe just one for the ceremony/cocktail hour? And have a second at the reception? I'm really hoping to stay around $2500 but am wondering if I'll miss out if we don't hire a second shooter!