So, when do you actually need to split things into a microservice?

hey everyone, im trying to figure out the right moment to extract a piece of functionality from a monolith into its own microservice. its easy to get excited about microservices, but i dont want to do it just for the sake of it. what are your signals or criteria for deciding that a service has grown too big or complex to remain part of the main application? is it team size, code complexity, deployment needs, or something else entirely? curious to hear your experiences and war stories.