HVAC Preventative Maintenance
I agree with ThreePhaseEel, no. If the unit is not in use, then there should be no reason to preventively treat the condensate drain-line.

However, you may benefit from adding water alone to the condensate drain-line monthly, if it's connected directly into the building's sewage system. If the condensate dumps outside or into a sump-pit or sink, then not even water is needed.

If you're adding bleach and/or vinegar to somewhere else, then stop it immediately as you should not be doing whatever you're doing...even if it's a humidifier. Otherwise, monthly to the condensate drain-line is not ever needed and only annually is more than sifficient.