It’s amazing how many people have “chains” or other door guards that don’t work. They also have deadbolt locks on their front doors but the locks are fastened to the wood with short , 1 1/2 or 2 inch, screws. If you want to deadbolt your door, be sure to use big screws, at least 3″ long. And screw them into the frame of the door itself.
By the way, I wonder how many people secure their front doors and then leave the back doors wide open, unlocked or unsecured? If you want to secure your home, you have to do *all* the doors.