Plenty of great content has been written about the problems Event Sourcing can help you solve. But after almost 10 years of using Event Sourcing in a distributed occasionally connected environment, I've experienced a lot of real-world challenges. In this talk, I'm going to talk about common challenges I've run into and the options I use to address them. I'll cover aggregate boundary challenges, problems finding the invariants, cross-domain communication, value types and events, versioning of events, eventual consistency of projections, projection bugs, time to rebuild projections, supporting blue/green deployments and more.