The breaker for our water heater was tripping a few times a day at the cottage. Since the normal breaker load should not cause a trip, I knew it’s either the breaker or an element was failing. Replacing the breaker was a 10 minute trip to the store and 5 minutes to swap vs. having to get a service call for the rented water tank.
3 days later, it appears that the breaker was prematurely tripping and we have hot water still.