Adjusting door hinges is very easy to do. It's a simple way to minimize wear and tear on the hinges, saving you from having to replace the hinges in the future. These are examples of when adjusting door hinges is necessary.
If the door is starting to sag, you can generally fix it by adjusting the screws on the upper hinge. This will tighten the hinge and pull back up on the door. Some carpenters will place a small piece of cardboard between the hinge and the jamb. This is an easy way to fix a sagging door without replacing the hardware.
If your door is popping open after you’ve closed it, or just not closing at all, check the hardware on the hinge. Chances are the hinge leaf is not fully set in the mortise. This can happen because of paint or other issues with the trim. For this, you generally need to remove the hinge and adjust where it screws in to the jamb.
If the hinge screws are too tight it can cause the door to become stiff, and possibly cause creaking or squeaking when used. If you're doing an adjustment like this, you'll need to be careful not to loosen the screws too much. Adjust the hinge slowly and continue to check the swing on the door.