Usually landing in your home airport, no matter how rough the trip and how late at night, is a great feeling.  A few years back, however, I had a horrible experience that led to a new travel habit.  I had a nightmare trip...5 cities in 3 days with a stack of conference calls to further complicate things.  There was bad weather with travel delays across the country.  My airline had screwed up my flights as well, so I had middle seats all the way home.  I arrived at 3AM, totally wiped out.  In Austin, TX, the airport is deserted by 10PM, so there was literally no one around, save a couple TSA guys.  I reached my car in the parking garage only to discover I had lost my keys somewhere during the trip.  Because my travel routine doesn't require me to use my keys (my car, house, and office are far away :-)  ), I never noticed.

The consequences were pretty painful that night.  The cabs were all gone, and I had to call one.  It was a $100 cab ride home arriving at almost 5AM.  I had to bribe a friend to pick me up and drive me to the airport the next morning to pick up my car.

My solution?  I now pack my keys.  When I arrive at the airport and am in line for security, instead of throwing my keys in a bin or bowl and sending it through xray, I clip them on a key hook in my bag.  All of my various pieces of luggage and laptop cases have one.  When I pull my carry on from the overhead bin as I land at my home airport, I unclip the keys and drop them in my pocket.

This has a few benefits.  In addition to ensuring my keys aren't misplaced, it also means my pockets are less full.  This helps since rental car agencies seem intent on providing you with multiple copies of your rental car keys, in addition to one or two remote door lock fobs and a rental car agency branded key chain the size of a coffee mug.