dont you really need a circuit breaker for when things get messy?

i've been thinking about resilience patterns lately, especially when dealing with external services or even internal microservices that might be flaky. circuit breakers seem like a good idea to prevent cascading failures, but i'm not sure when the overhead of implementing one is justified. are there specific metrics or failure rate thresholds you look at before deciding it's time to add a circuit breaker to your system, or is it more of a 'better safe than sorry' situation