I would agree with others that in a humid climate with 2 AC units running set low you are over cooling and not dehumidifying the space. I'd have a humidistat to see what level you have. If is indeed humid inside and out you do should use a dehumidifier. If it is only damp inside and very dry outside open a window or vent to remove indoor humidity. Condensation on a sink seems minor but as suggested it can be everywhere and cause mold in fabric, carpet, the mattress inside cabinets, in the closet, simply everywhere.