after awhile, when you leave the house and do that "mental" checklist...ok, keys, wallet, pocket knife, cell phone, firearm. 
Just yesterday, my wife and I just got into the car...heading to the grocery store. And I had this nagging feeling I was forgetting something. As any good wife would do, she was assisting with my memory...rattling off the list. I knew I had my keys (car was started), quick check...wallet, good to go...my knife was there where it should be...hhhmmm...awe...I forgot my cell phone...had to run into the house to get it.
By the way...I knew my firearm was in place, as it was the first thing I grabbed.
