A misaligned door could be the result of loose screws on the top hinge of the door, or a sagging door could happen as your house ages.
When a door is out of alignment, you may need to push or pull real hard to get it to close all the way. There may also be physical signs of rubbing, like tread marks on the frame or door itself. You may also hear the door rubbing and making a nose when it closes or opens. These are all signs that the door is rubbing against the frame somewhere and creating a security risk for your home.
If you neglect to have a rubbing door fixed, it could end up damaging the locking mechanism wherein you will need to pay even more to have the door repaired.
MAXIMIZE THE LIFESPAN OF YOUR DOORS
By not properly maintaining or repairing your doors and frames, misalignment will add to future repair costs and reduce the lifespan of your doors too. While it may not seem like much of an issue now, the pressure is being placed on components of the door, that will cause miscellaneous failures on things like door closers, locks, hinges and the frame itself. Those repairs can get costly, the longer they go unattended. Being proactive to maintain the alignment of your doors reduces long-term costs and helps you get the most out of your investment. SOURCE: The Flying Locksmiths
HOW TO PREVENT MISALIGNED DOORS
There’s no guaranteed way to stop misaligned doors or sagging doors from happening, but there are a few things you can do to prevent it!
A door that swells is the result of humidity. If a heat source is too close to the door or there isn’t proper ventilation in the area, this will cause the door to swell or warp. Ensuring that you have proper ventilation in your home is good for your doors—and good for you.
Another way to prevent misaligned doors is simply by checking in on the door hinges in your home regularly. Ensure that the screws in the hinges are tightened properly and that the strike plate hasn’t loosened.
The other preventative measure you can take is to stop doors from slamming. If you want to have the windows open to get a breeze through your home, use doorstops to prevent any doors from slamming shut in the wind. The slam of a door can easily loosen the screws or other parts of a door, leading to a misaligned door. SOURCE: MMDIY