When I was an active CFI and doing retract gear checkouts, I had one favorite way to distract a student. After numerous flights around the pattern, watching as putting the gear down became a habit, I would ask the student just before midfield downwind, “what’s your family doing for Christmas this year?” For a new retract gear pilot, it worked EVERY time to distract them. On final, with the gear horn blaring, I’d ask, “what’s that noise?” Most thought it was the stall warning. None noticed it before I mentioned it.
After finishing the lesson, we would talk and I’d tell them how normal their reaction was and hopefully they would carry the lesson forward with them. Our spouses (wives, husbands, doesn’t matter) notice our increased alertness in the traffic pattern and will pick that moment to start a conversation. I suggest talking about it beforehand, by telling the spouse about the sterile cockpit concept while in the traffic pattern.
Someone here (maybe @Hank?) has said their spouse has one job in the pattern and that’s to ask if the gear is down when on final approach. If I’d thought about that when I was instructing, I would’ve suggested that.
For single pilot operations I’ve always suggested the triple check: downwind- drop the gear and do the checklist. Base- verify green light(s). Short final- look at the runway numbers and say out loud “I’ve got the numbers, I’ve got a green light.” Hopefully one of those three will catch a mistake.
And I always try to remember “There but for the grace of God go I.”