We don't lock the door to our home unless we're leaving overnight. We never lock the car door. Actually, my wife leaves her keys (along with her wallet, ID, credit cards, etc.) in the car, unlocked, every night. I ride a bike everywhere and I don't own a lock for it.
In all honesty, I dislike that my wife leaves her purse and keys in the car overnight, but no matter how many times I've tried to convince her otherwise she never, ever, brings them inside. It used to drive me crazy, but we've been married for 5 years and I'm just used to it now. As far as locking the bike and our home - I just don't worry about it. I had a (locked) car broken into when I was in college, but that's the only time I've ever experienced a theft of any kind. Not worth the effort.