I misplace things all the time - I don't actually carry keys with me, not entirely for this reason but it's one less thing to worry about. Our garage door has a keypad, so I usually just enter that way.
But yeah, everything I carry around on a daily basis I've misplaced at least once. My phone, compass card (for the bus here), wallet, jewelry, etc. I say "misplaced" because for the most part, I've never seriously lost anything super important, and I've always been able to find/get them back. Jewelry would be the biggest casualty :( Like Sam, I have a lot of single earrings, but since I have 4 piercings I usually wear 4 different earrings anyway and pass it off as intentional. :P
Thank god for the "Find My Phone" feature though, right - it's saved me so many times