When is it time to ditch REST for gRPC?

im workin on some internal microservices and weve been usin rest w json pretty much everywhere. its familiar and works fine for most stuff. but ive seen grpc pop up more and more, esp for high-perf internal communication. im wonderin when the benefits of grpc like perf, schema evolution w protobuf, and streaming actually outweigh the added complexity of settin it up and managin it, compared to just stickin w rest. whats ur experience