when do u get a distributed tracing system tho

Hey everyone, I've noticed a lot more discussion about distributed tracing recently, particularly with microservices. As our systems get more intricate, I'm wondering when it actually becomes a must-have. Is it when you reach a specific service count? Or is it more about how complicated the communication between services gets? What's your experience been like when you first started using tracing, and what were the main signs that told you it was time to implement it?