In general, I don't have a weapon while I answer the door.
Today, though, I changed that. At around 11am, somebody rang my doorbell. So, I asked them through the intercom system who they were. The guy on the other end said, "Postman... [mumble mumble distortion] package for you."
But, I wasn't expecting any packages. Neither was my roommate. Furthermore, if it were the postman, he could have just left it in the entryway downstairs (I live in a three-unit apartment building). What's more, something just felt off.
So, I told him I'd be down in a second. Grabbed my pistol, slapped in a magazine of +P JHPs, racked the slide, and tucked it in the back of my belt under my shirt.
I went down and answered the door. Turns out it was the postman. No problem. But, I'm still glad I went with my gut feeling on that.