I bought these glasses as a gift for a family with 3 kids and expected they would be used everyday. When I talked with the mom she said that her kids wanted to save them for special occasions because they were so cool! I had them delivered to my house and when I checked them all of the batteries were dead. A quick phone call the company that makes them resulted in an overnight delivery of new batteries for each cup! They change colors every few seconds. The only drawback is that they ought not be put in a dishwasher which is not a problem for my friend. Her husband is her dishwasher.