Yes, you are expected to maintain your rental instrument as though you own it, this way good maintenance habits are developed so that when you decide to purchase a good instrument, you will already know how to care for it. Strings and bow hair should be replaced every six months for violins and violas. For cellos, the bow needs to be serviced at the same rate but the strings will typically last a year. Please remember that if you return an instrument that has not been recently serviced, you will be expected to pay for any upkeep that is needed to make it ready to go to the next player.