The problem circuit has 4 bathroom sockets, a front porch socket, and a back porch socket. Nothing is plugged into any of the sockets. A month ago, when I first became aware of the problem, the GFCI breaker would trip after 60 to 90 minutes. I looked into all of the sockets and replaced the front porch socket which was cracked. Lately, the circuit is tripping after 5 or 6 minutes, again with nothing plugged into any of the sockets. This problem has appeared suddenly after 21 years in the house. There has been no construction done, no humidity issues, no issues with weather or rain, or water leakage, and no new appliances. I am stumped. Any suggestions appreciated.
Change the GFCI breaker. These do have a lifetime.
The other possibility is that a receptacle (less likely a switch) on the circuit has gotten wet and is leaking to ground. Recently I had a roof leak into an exterior wall leak onto an external receptacle and trip the GFCI. Going off half cocked I replaced the GFCI breaker with another I had on hand. No effect. Only then did I remember that there was one never-used exterior receptacle on the circuit. I went out to examine it I saw water running down the wall from a leak around a plumbing vent.
I needed the circuit in operation immediately so I removed the receptacle and wired nutted the hots and neutrals and put a cover plate on the box. This stopped the tripping. I repaired the roof leak later.
If you think you have this problem, remove the cover plate on a suspected receptacle and direct a hair dryer into the box to see if the tripping stops.