I always carry a Kahr PM9 in my pocket even at home. The gun is so small and light it's really no big deal.
I live in a nice quiet neighborhood with a relatively low crime rate, but it's recently experienced a lot of burglaries and home invasions.
Two weeks ago, while I was at work, a burglar tried to enter the basement to my house. He smashed out one of the double pane windows, unlocked it, and attempted to squeeze through the other side. Unbeknownst to him my wife was home. She heard the racket, called the police, went down into the basement with her j-frame .38 in hand and let out a scream. He then quickly pulled himself back out the window and took off back over our 6ft. fence. Through all of this our neighbor, who is retired and was home at the time, claimed to not hear the glass being broken.
Since then I've replaced the window, installed burglar bars (a couple with inside emergency releases in case of a fire) and heaped heavy praises on my wife for being prepared. I hate to think what could have happened had the criminal gotten inside and she not been prepared.
The one thing I'd like to point out, that's mostly common knowledge, is that the burglar wasn't concerned about the alarm system. He never touched my phone line, even though it wouldn't have made any difference since my burglar alarm has a cellular backup. The alarm would have most certainly gone off had my wife not been home. The burglar's intent was to get in, get quick pickup items such as as VCRs, laptops, etc., and get out before the police arrived. They have a good idea of how long the process takes.