The service life of the bow hair of the piano bow has very strict requirements. Bow hair is a fragile product. Professional performers should replace the bow hair every three to five months; non-professionals should replace the bow hair once a year.
Bow hair often breaks one or two, please don't worry about this. Many people will pull it out directly by hand. It is recommended that you use scissors to cut it instead of pulling it by hand, because some bows will be pulled looser and looser at the two ends, because if the bow hair is disconnected from the middle, it is because of the piano. For a long time, this is normal. If the bow hair falls from both ends, it means that the hair on both ends has been loosened, so occasionally one or two of them are okay, it is not a quality problem.