When is Event Sourcing overkill?

hey folks, i've been seeing a lot more talk about Event Sourcing lately. it seems powerful for auditing and building different read models, but i'm wondering about the tipping point. when does the complexity of managing an event log, rebuilding state, and dealing with eventual consistency start to outweigh the benefits? what are your experiences, and when have you decided *not* to go with Event Sourcing?