How many times did I hear, "If you don't have it in your head you have to get it in your feet?" (Meaning, if you forget something you have to go back to get it.) Hundreds of times over the course of my upbringing.
So now, whether I forget something in another room, or forget it at home and have to drive back for it, I sigh to myself, "If you don't have it in your head, you have to get it in your feet - or your gas tank."
Don't you have similar bits of parental wisdom echoing through your brain now and then?