Same with the circuit breakers in the panel
I had no idea about circuit breakers going bad until I was working with a big router that kept popping my 15amp breaker, I ended up replacing it with a 20amp and then had the guy tell me that every time a breaker pops it takes less amperage to pop it again. It got to the point where that 15amp breaker was popping every ten minutes or so, it was big router...like a 3 horsepower.