Sometimes, it is a limitation of available material. The old hilt may be made from wood of very good grain, and it is not so easy to find another piece of wood of similar size and quality. Sometimes, its the quality of the carving. If the owner likes the form of the old hilt, he may choose to repair the hilt. Sometimes, its just sentimental/pusaka value... I'm sure there are many other reasons for repairing an old hilt.
