We strongly recommend all technicians carry a spare power supply. Not only can it be used as a standby for when the primary unit is being serviced but it can also be used if the technician works out of 2 different salons. It is not uncommon for cables to become damaged due to wear and tear and especially if you are guilty of wrapping the cable around and around before putting it in your carry case. Firstly try not to do this and secondly remember a spare supply is piece of mind that should your existing power supply become unusable you will never have to turn a client away or look unprofessional as you will have another to hand.