I do a quick check around to make sure I didn't shut one of them in a closet just before I leave, and I do look down to make sure one didn't squeeze past me when I stepped through the front door. I consider that very practical since I have had cats that dart into closets frequently, and out the front door on occasion. My Artful Dodger was quite capable of shooting through a door and up on to the roof in the blink of an eye. I once glanced back at the house to see him up there and, since he used the top of the door to get up and down, he would have been up there all day (a hot day) if I hadn't noticed. I agree with catnapper, that you should stop the re-checking now before you become tied to it.

I do tend to over-check on making sure appliances, etc. are all turned off. My fear is a fire while I am at work. The thought of driving up to my home to be faced with the fact that my cats perished in such a horrible way does haunt me. I could never, for instance, leave a television on while I was out of the house.