When you leave your apartment for work, school, or any other outing that will occupy a good amount of time, you no doubt make sure to close the apartment door behind you and lock it. But what about when you have to run a quick errand inside your building, such as to give something to a neighbor or do your laundry? The bottom line is, don't do it. Just get into the habit of locking your door anytime you leave the apartment, and you'll decrease the odds of getting robbed, or worse.
Not Just Neighbors
When leaving your apartment for a short time, it's tempting just to leave the door unlocked, so that you don't have to bother taking your keys with you and you can just walk right back inside when you return. But doing so opens the door (no pun intended) to crime, particularly from someone who already has gained legal access to the building, such as a neighbor, a neighbor's guest, or a delivery person. There also may be people who snuck into the building and are lurking about and checking for unlocked doors. In other words, even if you trust your neighbors, they're not the only people in the building.
You might think you'll be back in no time (such as if you're planning to check your mail or put more coins into the dryer in the laundry room). But what if you run into a neighbor and start chatting, or otherwise get distracted? If that happens, your apartment door will remain unlocked for much longer than you anticipated, increasing the likelihood of a crime. If you get into the habit of locking your door for all outings, you'll never have to worry about getting back right away, or about forgetting altogether that you left your door unlocked.
Criminals are much more dangerous when they gain access to a home and can operate without the risk of being seen by neighbors or others in the hallway. Leaving the door open—even for a few minutes—gives intruders silent and inconspicuous access to your home. Once they're inside, they can hide and wait for the right moment to victimize you without causing much disturbance. It is widely stated that criminals follow the path of least resistance. An unlocked door offers much less resistance than a locked door.
The Logic Argument
If you're like most people, you have the sense that if you do something risky only once in awhile, it's less risky than doing it all the time. This is true in terms of lowering the frequency of taking a risk, but otherwise the decision is not logical. Here's why: When you take a trip in a car, you always wear your seatbelt, no matter how long the trip is or how often you make a car trip. This is because you're not willing to take the risk of severe injury due to not wearing a seatbelt. And the risk exists any time you are traveling in a car. Likewise, the risk of an intruder entering your home is higher any time you leave the door unlocked. If you do it once a week or once a year, the risk is always the same. So, if you're deciding whether or not to leave your home with the door unlocked, you should ask yourself, "Am I willing to increase my risk for this convenience? Chances are, you'll decide that the minor convenience is not worth the risk.