Yes, it is on the seventh day. So it's always one day less in the week. If it happens on a Sunday, next week it is a Saturday (but when I reset during that week, it will "wait" seven days again). Basically exactly when the week is over. I will reset one today. Actually, was thinking of swapping one for a regular breaker. I am now wondering, too, if it is somewhere else in the house that trips them. But it would mean, that resetting the breakers does something to the offsetting device. Also, in the old part of the house we have Sqaure D AFCI breakers for the bedrooms, too, and they never trip. And there is a third AFCI in the new panel for the new bathroom (actually needs to be swapped for a GFCI; the contractor made a mistake) and that one never trips either.