The door hinges have a flexible tensile piece of steel that the door hinge acts against to provide tension when the door is open. Over time the original grease dries out.
If the grease has dried out, you'll hear a 'pop' noise when opening the door. This is a tell tale sign that new grease is required.
If new grease is not applied it is very possible and likely that the flexible piece of steel will break . If it does break the only fix is to purchase a complete new hinge...and that isn't cheap.
Needless to say I took the opportunity to apply new grease because my hinges were drier than a beer-fart-in-the-desert.
