Rinse aid is not required for every dishwasher to wash dishes, but it can improve water sheeting and reduce droplets, spotting, and drying problems, especially with hard water or items that retain water. If dishes already come out clean and dry, there is no need to add it automatically; if spotting or wet plastics are a problem, it may help.
Use it for droplets and drying, not as a detergent substitute
Detergent removes soil; rinse aid changes how water sheets and drains during rinsing. It does not compensate for a dirty filter, clogged spray arms, or incorrect detergent dosing.
Hard water and some materials make its effect more noticeable
Glassware and flatware can show mineral spotting, while lightweight plastics tend to hold droplets because they retain less heat. If the manual allows dose adjustment, start around the middle setting and adjust to the result.
If streaks or film appear, review dose and water chemistry
Too much rinse aid can leave a bluish or slippery appearance in some cases, while white film can also come from minerals or detergent. Change one variable at a time so the cause does not become harder to identify.
Use the system the manufacturer designed
Fill only the designated dispenser with a compatible product and wipe spills before starting a cycle. Do not pour rinse aid directly over dishes or mix products inside the reservoir.