It's always a good idea to turn the a/c on at least once a week to have all the internal parts lubricated, including the compressor seals.....Otherwise, the seals will stick to the shaft, and when turned on, the shaft will literally 'tear' the seals away.....
Lubricating the parts mean less chance of corrision to occur......
People always have a general misconception that by using less of the a/c system, the less likely it's gonna breakdown.....WRONG!!!!