I got a new car that automatically unlocks when you pull on the door handle with the fob nearby. It's so hard to not pull on the handles after locking to check. I've had the locks fail on me once on an older car so I'm always paranoid.
I got a 9 volt battery three weeks ago for my multimeter, at home I put it aside somewhere the cats wouldn't get at it to play with it and lose it on me.
I haven't seen it since. I have no clue where I could have put the damned thing.
I have a lock that I can check the status of on my phone, and even lock it from my phone if I forgot. It's really good for my peace of mind. No more getting up in the middle of the night to check the lock.