when to use a message queue versus direct API calls

hey everyone ive been thinkin a lot bout interservice communication lately. for simple req-response patterns direct api calls r pretty straightforward. but for tasks that might take a while, or where reliability is key (like processing an order), a message queue like RabbitMQ or Kafka seems like a good fit. tho, introducing a queue adds complexity managing consumers, handling dead-letter queues, ensuring exactly-once processing (if needed). when do u find the trade-offs really swing in favor of a message queue over just making a direct, perhaps async, api call? whats ur go-to strategy for decoupling services without over-engineering