Technically you don't need a second, but it is a really nice thing to have. The biggest problem a second shooter solves is the ability to be in two places at once. That means having one with the bride while the other is with the groom when they're both getting ready at the same time. That also means being able to capture the same moment from different perspectives, like getting both the bride and groom's reactions during a first look. And finally, it's a just another layer of security in the event something happens to one of us or our gear.