When should I think about using a message queue? You know, like for our projects?

hey all, ive been thinking about architectural patterns lately and the role of message queues. weve all seen them in diagrams, but when does it actually make sense to introduce one into your system? is it for decoupling services, handling background jobs, or something else? when did you first find yourself needing one, and what problems did it solve, or create, for you?