So, when does it actually make sense to add a message queue for services to talk to each other?

Hey everyone. I'm building a new microservices project and trying to figure out how services should communicate. Everyone talks about message queues like RabbitMQ or Kafka, but I'm not sure when you actually need them instead of just using direct HTTP calls. I mean, for a system with, say, 5 to 10 services and average traffic, is a queue too much to start with? Or are there times, even when you're small, that a message queue is just obviously better from the start? I'm thinking about stuff like making sure things only happen once, handling too much traffic, and how complicated it all gets. I'd love to hear some actual examples or how you guys decide.