What have you lost more than once?
My favorite pen. I use it so much that it's bound to get lost every now and again, but that doesn't make me any less frantic every time it goes missing!
It counts after you're born again, right?
Remotes! Those damn things are always walking away. Technically, most of the time one of my kids or my wife do the losing and I do the searching, but I've lost them plenty of times myself. For me, a phone with an IR blaster is an absolute must.
I swear I am going to weld those damn things to a chain and lock it to a cinder block. My son always throws them wherever and it takes me 15 min to find them.
Files, because I was procrastinating making back-ups.
I lost over 10 years of gathered things because of a dead drive. I feel you on that one.
My glasses. But I usually find them on my head.
Keys, wallet, shades... the things I take with me are generally at the most risk of getting lost. Ive been better the last 10 years but when I was younger it was definitely a semi-regular occurance!
My birth certificate. And my cell phone, mostly because I hate cell phones.