when do you add async stuff in, like maybe when you have tasks that dont need to finish right away, bc theyre just

So, I've been thinking a lot about when it's actually the right time to switch from standard, synchronous API calls over to asynchronous processing with something like a message queue. We talk a lot about breaking up monoliths or using gateways, but moving to async seems like a separate, and often earlier, decision. What makes you guys pull the trigger on async processing? Is it just about latency, or do you also consider things like decoupling services or dealing with background jobs?