I just carry when I am in the house. If not carrying then I have one very close by. I live in a rented duplex so alarm system is not an option. I did reinforce the doors. The windows are plexiglass, and secured fairly well. They will not shatter from a strike. I know they would not stop a determined intruder, but it would slow them down for a few seconds atleast.
I have a dog. Though he would have to drop his ball to be effective against anyone. I doubt he would bite anyone. He does let me know when my girlfriend is home, or when the girl scouts are at the door to sell cookies. He gets happy then.
Due to the neighborhood my biggest concearn would be a case of wrong house home invasion. They have had a couple of them happen here. All counts the victim knew the attacker. All but one were to rob the house of drugs, and money. One was a case of wrong house. When the invaders figured out that they had the wrong house, they stabbed the elderly man that lived there, and fled. Luckily the man only suffered from non life threatening injuries. The three attackers were caught less than 20 minutes later. All were sentenced to 80 years each.