The milkman went to every home and delivered fresh milk
In films film set in the 1950s or 1960s, there are clichéd scenes showing the milkman’s truck on his way to leave fresh milk to the families. This job was crucial back then as people in the suburbs and cities no longer had cows or a way to preserve their store-bought milk.
Before pasteurized milk was invented and refrigerators became common household appliances, milkmen had to deliver milk jars to each home every couple of days. Otherwise, it would have easily gotten spoiled. However, milkmen were no longer necessary when people started to have refrigerators in their homes, and the occupation disappeared.