Use it, or lose it.  Turns out, this expression applies to our brains, and research now indicates that excessive use of GPS navigation devices may contribute to actual brain shrinkage. 

The area of the brain that helps with spacial navigation is known as the hippocampus, and decreasing the amount of stimulation to this area can lead to impaired memory, and may be a contributor to symptoms that eventually lead to Alzheimer's Disease.

I'm an early adopter, which means I pay more for electronic gizmos long before they become mainstream.  I've become dependent on my GPS, and if you've come to rely heavily on yours, you know sometimes you can arrive at a destination, with very little knowledge of how you arrived there.  Our brains are on auto-pilot, and we're turning into "GPS Zombies".

Psychology Today offers two suggestion to avoid becoming a GPS Zombie:

1) Mute your GPS. That wacky voice on your Tom-Tom was annoying you anyway. The device will still visually guide you to your destination, but you'll be responsible for finding the upcoming street name.

2) Use the GPS to get there, but use your brain to get back home. Remember those funny TV shows when you were a kid, where someone would drop an unwanted pet in the woods and they'd show up on their doorstep hours later? Try to be that pet.