when should you use a circuit breaker pattern, I guess?

hey everyone, ive been thinking about service-to-service communication in microservices lately. weve got a few critical paths where one service directly calls another. if that downstream service starts to misbehave or become unavailable, our main service can get bogged down with failed requests or long timeouts. ive read about the circuit breaker pattern and how it can prevent this cascading failure. has anyone implemented this? what were your triggers for introducing it, and did you find it made a big difference in system stability?