when do you really need to think about using a message queue tho

Hey everyone, hoping to get some collective wisdom here. We've been pushing a lot of data between services synchronously, and honestly, it's starting to feel brittle. Callbacks are getting messy, and we're seeing cascading failures when one service hiccups. I've seen plenty of architectures use Kafka or RabbitMQ, but I'm wondering at what point does the complexity of managing a separate message queue system outweigh the benefits? What are the tell-tale signs that synchronous communication is no longer working and a message queue becomes a necessity, not just a nice-to-have?