Ask the Experts: how often should you have your bow rehaired?

The dilemma My bow probably needs a rehair (there’s a tuft of broken hair ends near my frog!), but I’ve been so busy doing my office job during the day and playing chamber music in the evenings that I haven’t had time to get it seen to. Will it harm my bow if I keep playing on it anyway? And what’s the longest anyone should go between rehairs – does the hair deteriorate even if it’s not being used?

JUTTA WALCHER Developing a ‘tuft’ of broken hair ends near the frog is usually the beginning of the end: it is a sign that the hair has worn out and it will continue to break at an ever-increasing rate. This will lead to the stick being pulled over to one side when under playing tension. I have come across bows where the wood has been worn away as a result of a lack of hair on the playing edge – damage that cannot be fixed. When receiving a bow in this condition, I occasionally wonder how the player ever managed to keep going with half of the hair missing!

Watch out for how much the hair has stretched. As the number of the hairs...