Yes, you should. At least every couple of weeks for 15 minutes, as this will allow the refrigerant to circulate through the system.
The lubricant in the refrigerant keeps all the rubber seals and pipework in good condition, otherwise it can lead to leaky seals and more re-gasses. Without frequent use, moisture can also build up within the air vent ducts causing mold and bacteria which are then blown into the car when you start the system again.
We can do a professional check of your vehicle air con system, to make sure you'll have a safe and comfortable driving experience through both the warm and the colder months.