Need? No. And if I were a litigation attorney who made money off of people’s mistakes, I’d say don’t have one and let the chips fall where they may — better yet, let state law govern your rights and duties. But I’m in the business of preventative law. So, yes, you should have an operating agreement. Just by way of example, without one, and your partner dies, you’ll become partner’s with your dead partner’s surviving spouse — think about that one for a minute. No way out of that without a written operating agreement providing for a buy-out.