Introducing a circuit breaker adds a small overhead to each call, since the program has to check the breaker’s state and update counters. However, this overhead is usually minimal. In fact, it’s a negligible cost compared to the potential performance degradation of not having a circuit breaker. Without a breaker, a failing service call might tie up a thread for several seconds until a timeout, whereas with a breaker the failure is handled in milliseconds. In other words, a tiny check is a small price to pay for avoiding a meltdown