On Monday, October 29, 2018 at 1:57:35 AM UTC-4, Oumati Asami wrote:
Usually, I have A/C serviced every six months. There is this A/C which I
have not used for the past six months. Does it still need service?

What kind of AC and why does any AC need service every 6 months? If
it's being used frequently, then clean or change the filter. End of
story, unless it's defective.