How Long Do GFCI Outlets Last?
A worn GFCI can still pass power to a lamp or tool perfectly well while its internal fault-sensing circuit has drifted out of tolerance and no longer trips fast enough at a dangerous fault current.
Why 'it still works' isn't the same as 'it still protects'
A GFCI's core job — sensing a tiny current imbalance and tripping fast — depends on precision components that wear with age, humidity exposure, and the number of times the device has actually tripped. None of that wear is visible from the outside, which is exactly why the monthly test button exists.
Outdoor and bathroom GFCIs tend to age faster than dry indoor units because of repeated humidity and temperature swings.
A practical replacement rule of thumb
Test monthly using the built-in button. If a device ever fails that basic test — won't trip, won't reset, or stays powered through the test — replace it immediately rather than leaving a non-functional safety device in place.