On your way out … oh no, did I forget to lock the front door a moment ago? When I am in a hurry I often think I should go back and check. As you put on shoes you’re subconsciously aware of what you’re doing from closing the door to turning the key. More than likely I am hanging the key back on it’s hook. It’s a waste of time and something I don’t want to think about when I am in a hurry.
Anyway, I found a useful solution to solving this problem with​ ​ChecKEY.​ ​
I am actually began using right away, but for now can be seen in this image as huge. It’s unlikely to be a so rigid (only once a hard key has been turned is it released after inserting?) so, would like some discreet variations in size, and different colours, like black, to be made available.