If you or someone you live with has accidentally knocked a hole in a hollow door you can fix it with materials available at your local hardware store.
Repair hole in hollow core door.
I would either replace the entire door skin and refinish it or more likely buy a new door and stain and finish to match.
If the screws in your door hinge have become loose and frequently require tightening or have been tightened so often that they no longer stay securely in place causing the door to sag most likely the wood sections the stiles that frame the inside of the door need reinforcement.
These relatively flimsy doors can be damaged easily.
While holes in your doors or unsightly scratches might seem difficult to repair you can get them fixed up in no more than a day or two.
The best hinges for hollow core doors are still the base molding spring stops as seen on the door in this foreground and not the hinge pin stops as seen on the two doors in the background.
Hollow core doors are common in the interiors of houses and apartments.
Now if the hole in your door was caused by a hinge pin stop replace it with a different type.
Hollow core doors are much cheaper and more common than doors made of solid wood but they are also a lot more fragile and prone to damage.