Where's the Dang Key?

I can't believe I had to break into my own house again. Third time this year. I keep a key on a nail under the back porch, and I always hang it back up after I use it. But for some reason it doesn't always work when I stick it into the lock.

My paranoid side thinks that someone is stealing the key and filing down some of the unique shape along the edge that goes into the lock. And my sensible side can't seem to come up with a better suggestion.

I know what you're thinking. Just keep a key with you, stupid. Well, I used to do that, but I lost three keys that way. Hole in the pocket. Key pops out when I pull something else out. Magnetic force from a passing alien. Who knows? Bottom line is that I decided that taking the key with me wasn't a good idea. My keys have a habit of disappearing into the ether, never to return.

I've thought about stashing several keys in various places around my property, but with my luck, someone probably will steal some of them, and I'll forget where I hid some of them, and, who knows, maybe that passing alien will beam some of them up as souvenirs of his/her/its visit to Earth.

Anyway, I think I've come up with a solution. I'm going to sell everything of any value, and just leave the house unlocked. That's so crazy that it just might work.