I ALWAYS answer my door with my .44 in my hand (behind me out of sight)..... just sayin’
I live alone and our small group of townhouses has a gate so cars aren't coming in unless they live here. During the day, I leave the metal door open with the locked glass door in front of that. I do that so my Yorkie, Prissy, can see outside and if anyone/anything moves as far as she can see, she has a barking fit and runs to tell me. I just turn my head and can see whatever she just saw and have plenty of time to react.
Today, she started having a fit and ran to me, so I went to the front door. A firetruck and ambulance had quietly come in and parked in the street two doors down from me. I never would have known they were in here if she hadn't alerted me.
When it gets dark, I lock my door and put the heavy duty Buddybar under the knob and it can't be kicked open. If the doorbell rings after dark, I don't go to the door. My safety is more important than whatever someone out there wants.