This system is easy to learn, and has worked very well for us. Even three year olds can learn it! We have a wonderful supply of unique cups gathered from garage sales and thrift stores- no two are alike! Everyone is happy to select their favorite.  It has saved not only thousands of gallons of water over the years, but also reduces clutter- no glasses strewn all over the house. It also saves a lot of time when washing the dishes because there are roughly one-fourth fewer dishes! Save money, save time, and save the environment all at once!