I have a place where I agreed with myself to "always" leave my keys when I am not using them while in the house. On the nightstand, next to my bed. Well, then the search starts after I have absentmindedly dropped them somewhere, anywhere, etc. The worst is when I have absently put them in a pocket and then later hang that garment in the closet!
I have two sets of keys. When I get to the 2nd set, I frantically wrack my brains and search the whole house looking for the last place I randomly dropped them.... I do have a mental list of all the random places I have found them in the past. After all, we have our random acts of inattention habits and mindless patterns, so use these if you run into trouble finding something like your keys!