If you do install an alarm, check with your insurance company. Many offer rate reductions. Get in the habit of locking doors and windows before you leave the house. Activate your alarm if you have one. Follow the same pattern every time you leave so you don't forget anything.
Burglars often use an attached garage to enter a home.
It can be much easier for them. Once he's inside the garage the thief can take his time defeating any lock on the door that leads inside your residence. Since they're hidden from view it's unlikely they'll attract any attention. If you're going to be away overnight or longer, you want to make it appear like you're still home. Naturally you'll want to have the mail and newspaper deliveries stopped.