It's important to use an automatic defrost functioning refrigerator to accumulate moisture build-up and turn it to frost. Many such refrigerators feature the defrost function as it's rather inconvenient to take out all the food items from the cooler and then defrost them. But, this kind of disturbance isn't seen in mini or compact fridges as they give out somewhat of a low temperature and has many restrictions. In these cases, an automatic defrost isn't needed.