whens the right time to implement a message queue?

hey folks, i've been thinking a lot about asynchronous processing lately. we're at a point where certain background tasks are starting to slow down our main request threads. i'm curious to hear when others typically decide to introduce a message queue like RabbitMQ or Kafka. is it purely performance-driven, or are there other architectural benefits you look for? what are the tell-tale signs that it's time to move from direct calls to an async queue