Did you ever have to replace a carpet, sofa or chair because of only one unsightly area? Maybe there was a spill that caused a permanent stain, a pet clawed at the fabric or possibly an unusual wear area or tear. People often feel they must resort to replacing furniture or rooms of carpet because they know it is almost impossible to purchase a matching piece of fabric or carpet to do a repair.
But you probably have an exact matching piece of fabric or carpet that would make the perfect repair. The largest single piece of fabric on the typical sofa or chair is the fabric on the outside back. This area is generally large enough to cover at least one other entire section of the upholstered piece. In many cases no one sees the back since it is usually against a wall. A good upholsterer can replace this with a coordinating fabric and use the original fabric to make the repair.
The same principle also applies to repairing the damaged area of a carpet. Did you save the leftover scraps of carpet when it was installed? Assuming the directional lay of the nap lines up, and there is not a significant change in appearance due to use, this can be an excellent source of repair material.
If there is no extra carpet, the next option is to literally swap the damaged carpet with that of an unseen location such as a closet or from under a bed or other piece of furniture. A good carpet installer can carefully remove the damaged section and cut a matching piece from the unseen location to replace it, for a bonded insert.
If you have matching carpet throughout your house and are considering replacing all of it, because of a large damaged area, you could use the carpet from an entire bedroom for the repair. Then you can replace the bedroom carpet with a new similarly styled carpet.