Vivekanand Vellanki

Door hinges allow a door to rotate around the door frame. Doors are usually on a wall and provide access to what's beyond the wall when the door is opened.

Most doors are next to a wall - hence, there is no need for the door to move more than 90 degrees.

Some doors are in the middle of a wall and the door can actually rotate 180 degrees. Door hinges that allow a door to move 180 degrees are required for this.