I have a bad habit: I will lose anything if it's not attached to me.
When I get home at night, my routine is my keys go into a tray by the door. My phone, I keep on my person and I have a place where I plug it in and charge it at night. My wallet, my glasses, my watch, and my wedding band all go the same place every single time.
So I always know where those things are. But too many people lay things down and can't find them.
Now, there are a number of things to help me and others keep track of our gadgets that I read about in The Wall Street Journal.
StickNFind makes tiny sensors with adhesive tape on back that are a little thicker than a quarter. You stick them to your gadgets and they can emit a sound to help you find lost stuff. But they're way too expensive at $25 a pop.
Another one for iPhones is called the hipKey. That one can help you find the iPhone 4S and 5, for $90 a pop! Then there's also the Proximo, also for the iPhone 4S and 5, at $25 a piece.
If you're cheap like me, you're an Android person. So I suggest you load Lookout to help you find a lost phone.