When should we consider using a distributed tracing system?

i've been working with microservices for a while now, and as our system grows, understanding the flow of requests across different services is becoming a real challenge. debugging issues that span multiple services can be incredibly time-consuming. i'm starting to think about distributed tracing. what are the key indicators that tell you it's time to implement a system like Jaeger or Zipkin, are there specific pain points that signal the need, or is it more about proactive architecture planning