I usually don't lock my car when I leave it in my garage. But when my bike is inside my car, I lock my car. I'm more afraid of my bike being stolen than of my car being stolen. I figure a thief won't bother to break into my car to steal it, but they would break into my car to steal the bike inside it. My car is a '92 Honda Accord with 215,000 miles. My bike is a Giant Rapid 1 with over 2,500 miles on it. Most of the car miles were from when my dad drove it, he gave me this car when I turned 16, and I've taken care of it ever since for 8 years. In the past year, I've put more miles on my bike than on my car, and I do more maintenance to my bike than my car. In fact, this year I've only filled up my gas tank twice. It's not unusual for me to leave my car in the garage unused for 2 weeks, and I sometimes am "forced" to take the car out for a drive just so the battery doesn't die.