whens it time to ditch your monolith?

So, we've been running this big ol' monolith for ages. It's worked okay, but lately, coordinating deployments, figuring out all the testing, and just getting stuff out the door is getting really slow and complicated. We're thinking about switching to microservices, but honestly, the upfront work and all the tricky stuff with distributed systems seems like a lot. Has anyone else done this? What was the hardest part, and what would you tell a team thinking about making the jump?